Starting with paint rollers
Take a roller tray and pour a generous amount of paint in it. It should take up at least half part of the tray. Moisten the roller with water if you are using latex or any other thinner. Remove the excess water from the paint roller with an absorbent cloth. Take care not to use a cloth that bleeds color to lap up the excess water. Now use the roller and roll it up and down the tray with paint so that every portion of the roller is covered with paint. Make sure that the roller is not dripping with paint or else you will have a big mess and waste paint. Once the roll is covered with paint, roll it in vertical swipes up and down the walls. Paint the wall to your satisfaction, let it dry and examine it because usually it will require another coat of paint so that the primer does not show through. The roller should always have enough paint on it so that you are able to roll it smoothly across the wall without having to press hard to get the paint on the wall. Once you are done with one area, lighten up on your rolling action as you remove the roller from the wall so that it does not leave a mark. Make sure each area that you paint merges with the next area you paint.
How to apply paint evenly
Once you have selected a paint roller and you have the paint on the roller then start applying it in a vertical but zigzag fashion, never lifting the roller off the wall unless you need more paint. By following this method, you will apply the paint more evenly resulting in a solid looking paint job. Do not allow the edges of one are to dry out before you paint the area adjacent to it because it will stand out once everything is dry.
The Advantages of using a paint roller
The major advantage of using a paint roller is the speed and versatility that go with it. You can finish the job quickly all by yourself. Paint rollers come in different sizes with adjustable handles. If you want to cover a small area, you can use a 4-inch roller; if you want to cover a bigger area, you can use a 14-inch one. You will get commendable results with a paint roller whether you use it on the exterior or the interior of the house. To get the full advantage of a paint roller, remember to use one with a good sleeve. Buying an inexpensive sleeve works for short term painting jobs, but to get the desired results its better to purchase a half-inch thick wool sleeve because you need a roller that holds more paint and spreads more evenly. If any retouching needs to be done, you can do it quickly with a roller, but remember to do it when the paint is still wet enough. Overall, this is the best way to get your painting job done and you will save a lot of money on paint.
It is better to use a roller that has a longer nap length when you have a rough surface. Using short ones for smoother surfaces would be sensible because you can do the job easily without any unpainted surfaces in between.