Spray painting is usually used when large area needs to be painted the same color, or on rough exterior surfaces where pressure is necessary to achieve good results.
Most of the painting contractors use airless sprayer. It is called airless because it doesn't use compressed air. Instead the paint is forced though the small hole in the painting tip by the pump, producing the same result as conventional sprayer. The overspray is a drawback of an airless sprayer, because it usually means considerable loss of paint and a lot of masking prior to spray painting.

Here are some of the basics of spray painting.
The gun is held about 8 inches away from the surface. If the surface is smooth it is spray painted at the straight angle, if it is rough it may need to be sprayed at different angles to cover previous color. The paint overlapped 50 percent in order to cover the surface well and not to leave any lines.
If the surface after spray painting is not uniform and paint lines can be seen, there may be a few reasons for that:
A spraying tip is too old and worn out, and needs to be replaced.
The pressure is not adjusted well, and pressure settings needs to be changed.
The paint filters are clogged up and need to be cleaned or replaced.
The spraying tip is too large and the pump can't produce enough pressure to support the tip.

Reversible painting tip and extension for the gun can be very helpful. Using reversible tip will save a lot of time, if the the tip clogs up often when the paint is not strained well. Painting extension with adjustable end, can save a lot of time by not having to climb up and down the ladder when painting a two story house.

A lot of houses in Arizona have rough textured stucco for the body of the house. If the color change is desired, instead of trying to spray from different angles, trying to cover previous color, a better solution would be to spray at a straight angle, as if painting a smooth surface, and then use a roller for the second coat. Pushing the paint inside the stucco with a roller cover for rough surfaces will give much better results, than applying two coats with the sprayer at different angles.

Spray painting is the easiest part as it can be learned very fast. It is the preparation work that requires a lot of experience. One can learn how to spray paint after painting 3-4 houses. However if a home owner is considering to do spray painting himself, he may find that it is not as simlpe as it looks. Home owner will always save money and frustration by calling professional painters, that have already made all the mistakes on someone else's house and have the experience to do quality work.