Painting a room is one of the easiest things you can do to enhance your surroundings. Its mostly fun, fairly inexpensive, and can be a very satisfying accomplishment if done well.

It's a Long Job
Painting a medium room takes about 12 hours of work. If you rush in, trying to get a room painted in one night, you are going to end up exhausted with white doorknobs and hardened trails of paint dripping down from forgotten nails. You might be able to get it painted in one night with three friends, but if you can't recruit three friends, plan on it taking a few days at least.

Choosing a Color
The paint department of any hardware store will have dozens of free color cards, known as "paint chips", to bring home and tape up in the den.

Buy some 12-ounce test paints if you aren't sure how a particular color is going to look on the walls back at your house. These cost $3.50, which is a lot for 12 ounces, but worth it if you end up not liking the color.

Glossiness
In addition to color, you'll need to choose a glossyness of the paint, either non-glossy "flat" and "eggshell" to "semi-gloss" or "glossy". I recommend painting most rooms with eggshell walls, flat ceilings, semi-gloss trim.

Bathrooms and kitchens usually get semi-gloss walls and trim.

Equipment
You need a roller, a roller pan and a brush.
If you are starting from scratch, buy a painting kit, which will provide the minimum tools required. Buy more rollers if you are recruiting friends to help, but you might just want to share the first one, because the more you use, the more you have to clean.

Don't clean the walls
When I learned to paint, I was taught to clean the walls with a TSP mixture. But then the main ingredient was banned, so no one sold TSP anymore, so I started using TSP substitute. Finally, I decided that washing (and rinsing!) the walls first was a huge wet pain in the ass, so I stopped doing it. I haven't noticed any difference at all in the final result, so when it comes to washing the walls before you paint, my recommendation is: Don't Bother.

Move Furniture
Take down blinds, curtains, outlet plates, clocks, frames, mirrors, posters
Don't leave any residue from adhesive squares or double-stick tape. You can't hide that with paint.

Its possible to paint around one or two big pieces of furniture, but it will really slow you down, especially if it is going to impede your constant trips to the roller pan.

If something appropriate is available, keep one waist-high piece of furniture in the room to use as a work table. Cover it with plastic film or a tarp. You need something in there, or you'll end up putting all of your tools on the ground, which is not a good way to work.

Protect the floor and windows
Tape off stuff that you don't want to get paint on. Use masking tape to tape down one edge of a roll of paper. If you are planning on painting the whole ceiling, spread out a drop cloth or plastic film to prevent damage from spills.

I usually use an 8" wide strip of paper along the walls, and plastic film to cover the rest of the floor. I also use paper under the door, because I always get a little sloppy when I'm painting big trim elements.

More preparations
Set up lights - If you are painting at night, you'll need extra lights to get a good look at the paint as you put it on, to see details and where the old paint color might be showing through.

Fix Holes
Paint won't fill in holes. Fill anything bigger than a sewing needle hole. Don't paint over nails.

Use a tube of caulking to fill long, thin gaps, such as the gap between walls and moulding.

Use spackle to fill nail holes, doorknob impact craters, old curtain hardware holes, bullet holes, etc.

I find spackling to be very easy, probably the most fun part of preparation.

Remove plastic plates over electrical outlets and switches. This is very easy and safe. I usually put masking tape over the switch within to prevent it from catching any drips or errors.

If a switch or outlet looks worn or ugly, switch off the power and wire in a new one. These little fixtures are very cheap, priced between 50 cents and $3, and can greatly improve the look of a room.

If you are afraid or not skilled enough to re-wire a new outlet, consider freshening them up with spray paint and a paper mask.

The completed outlets look great. Buy new plate covers if yours clash, are cracked, worn or ugly. New ones are about 50 cents each.

Dress appropriately
Even if you are slow and careful, you will still get paint on your shirt, and on your pants, and probably on your shoes. My specialties include: ruining pants by kneeling onto a glob of wet paint and dragging my sleeve on the rim of the roller pan. Its just faster to change into some crappy clothes and forget about it.

Oh My God. You Might Be Ready to Paint.

Paint with rollers
Don't even think of painting a room without a roller. Rollers are about 15 times faster than brushes. In addition to the walls themselves, you should plan to paint as much of the trim as possible with rollers.

"Power" Rollers which force paint onto the roller work fine. Some use muscle-power and some have electric pumps. Both kinds work pretty well, especially for bigger jobs. Keep in mind that painting the big flat areas of walls is the easiest part of painting, so they can only help so much.

Paint hard parts first
It doesn't really matter, but I recommend progressing as follows:

1. Paint the ceiling (optional)
2. Paint the trim
3. Paint the walls

Its fun to paint the walls. It is not fun to paint the ceiling. When you start, imbued with enthusiasm and energy, paint the ceiling. Then paint the trim. When you are tired, and a little sick of painting, you will have saved the most fun part for last - painting the walls themselves.

I decided this big closet door is "trim".

Painting the ceiling can be exhausting, because you have to do it over your head. If you are standing on a chair, your legs will tire quickly because your feet will be tensed for balance. Also, unless you are an expert roller-pan placer, you'll have to go up and down continuously to get more paint on your roller.

Although the trim (including doors and cabinets) will have a much smaller surface area and require a smaller quantity of paint, the trim takes time because the surface is complicated and there are more obstacles to avoid.

Where two colors of paint are going to meet at a border, go ahead and paint past the border with the first color. With the second color goes on top, carefully paint right exactly to the border. This will end up being a little faster and it will avoid having a thin unpainted seam between the two new colors.

Clean up as you go
Don't be messy, but don't obsess over every speck. Keep a damp paper towel in your back pocket to whisk up drips before they dry. It puts a hitch in your rhythm, but drips are 3-5 times harder to clean if they dry before you get to them.

Paint thoroughly
Its easy to paint with a roller, and 96% of the surface will be covered with the first pass of a fresh roller. But you've got to get that last 4%. If you don't, especially on a bumpy wall, you'll be able to notice dots of unpainted wall all over your work. Go over it again for a professional finished appearance.

Fill in the "W" with horizontal rolls.

Beginning painters will quickly develop a sense of when the roller needs more paint.

I haven't been counting, but I'd guess that a full roller is good for about 20 strokes before it needs a paint refill. It'll keep painting, but it does a progressively worse job after the first dozen strokes.

Your hands will get tired.

Rough it out, then cut it in.
Rollers are much faster than brushes, so do as much as you can with rollers.

When you get to edges, roll as close as you can without getting paint over the edge. Fresh rollers apply a lot of paint, and if you work quickly, you can come back with a brush and distribute this edge supply with a brush.

After the roller, come back with a brush and fill in the rest of the paint up to the trim. This takes some practice.

"Cutting in". Filling in the gap of unpainted wall between the rolled part and the ceiling.

More Painting Tips

During the course of painting a room, you are going to run out of a few things and will need to make a run back to the store. You actually might need to make 5 trips, so try to hold off until you have more than one thing before you actually go.

If you need to order more paint, bring the paint can lid, or take a snapshot of the lid label to show the paint counter guy or girl.

It is easier to see painting errors when adjoining colors contrast sharply. The closer the wall and the trim color, the better your errors will be hidden.

Applying this chocolate brown next to white trim in our hallway took a lot of time, and is obviously still flawed.

I don't recommend using any kind of rolling edge-painting tool. Maybe someone can get these to work, but not me. Just use a brush for details like that.

When you are done painting everything, spend a few minutes looking back over your work. Don't quit immediately.

You will probably find 30 little trouble spots which need a little help.

This probably sounds crazy, but it's something that happens: Don't leave a strip unpainted between the ceiling and the wall just because you are afraid to get the wrong color on either one.

It's more important to have the two paint colors meet along a straight border than it is to have them meet exactly at the corner where the ceiling and wall meet.

It's a little better to have wall paint on the ceiling than it is to have ceiling paint on the wall.

In the case where there is a little pebble-line of leftover popcorn ceiling texture in the crease, I recommend painting the wall color over the popcorn and onto the ceiling a tiny bit, creating a straight line between the colors.

Washing out rollers and brushes is time consuming.

One short-cut, if you will need a particular color the next day, is to wrap the roller in a plastic ziplock bag and to throw it in the freezer.

The frozen paint will not gum up brushes and rollers. You just have to give them 10-15 minutes to defrost before you use them the next day.

When you are actually done with a color, and it is time to clean the brushes, clean them out very well.

It takes a long time to get all the paint out, but if you do a half-hearted job, or even a 90%-hearted job, the remaining paint will lock the bristles together and you'll have a brick on a stick.

Don't clean them outside with a hose in the gutter. Gutter water isn't processed before it flows to rivers and lakes, so make sure your paint water goes into a sink or toilet. You can do it outside in a big bucket, but dump the bucket into your toilet. I know, it seems backwards, but that's the right thing to do.

For the roller covers, it takes even longer to clean them out. They hold a lot of paint. If you really hate cleaning them, and don't mind chucking $3, you can just throw them out. I'm a pretty cheap person, but cleaning these things after a long night of painting can be a losing proposition.

Without a doubt, the best part of painting is pulling up the masking tape and seeing the finished look of the newly painted room.

It won't be perfect. Clean up any spots where the paint crept under the tape.

Replace the electrical cover plates, put the drapes back up and move in the furniture.

Bask in your achievement!