Paste and powder paints should be mixed in quantities sufficient for immediate use only, as these materials often become unfit for application if allowed to stand for three or more hours. When it comes to rolling out the walls never ever use a cheap foam roller. Foam rollers never evenly absorb the paint out of the pan and will actually add time to you project and cause more mess. Buy yourself a synthetic professional 3/8 nap roller head for about $6 to $8. Not only will the paint be applied in a smoother fashion you will experience less work and mess. Painting trim is normally done by roller and brush, not sprayed, so more manual labor is required painting trim, and most cases costing 60% of the total exterior painting job.
The second part of preparation is surface prep, it addresses covering the surfaces you do not want to get any paint on. A little plastic sheeting will go along way to keeping paint off of floors, window coverings, handrails, cabinets, counter tops, etc... And, if you are not confident with your ability to paint a straight line next to door casing, baseboards, cabinets or hardware protect these surfaces using masking tape. There are two basic types of masking tape white/yellow and blue. The white tape sticks to surfaces better but, can pull off finishes on cabinets or stained woodwork. Blue tape usually will not pull off finishes but, does not stick as well, this will probably be the tape to use for most applications. Always wipe down or dust the surface you will be masking to assure the best tape adhesion possible. If you use blue tape you may need to re-rub down the tape before painting next to it, only mask off areas with blue tape that you will be painting for a given day. With either tapes, do not assume the are a force field that paint will not penetrate, use them as a reference and dry brush the paint next to the edge of the tape and avoid soaking the edge of the tape with a lot of paint, this will cause the paint to "bleed" through giving you an undesired look. If you will need to apply multiple coats of paint, on the first coat, paint as close to the tape as you can, not really getting paint on the tape. With the second coat or a one coat application, you can use the tape more of like a paint barrier and get a little more paint on the tape if you immediately remove each section of tape after painting the section, this will keep the paint from sitting on the tape and "bleeding" behind it. Also, if you get a lot of paint on the tape it is not good to let the paint dry on the tape because some paints (especially the glossier paints) will peel if allowed to dried, with the tape when it is pulled off. White tape should not be left on for longer than a couple of days and I suggest not leaving it on more than a day in areas that receive long periods of direct sunlight. Blue tape can be left on for days, if it will stay on, there again it does not stick as well and may need rubbed down again immediately before painting up next to it. If you have large holes or cracks in a wall purchase a small can of vinyl repair paste. The reason I prefer it over regular wall Spackle is that after it dries it is much harder and sands easily. You can even use it for minor wood repair in a pinch. Painting the exterior of your house requires a thorough estimation, visualization and preparation. When you have chosen your theme for your rooms and have bought the job materials you need. There are 2 methods for using primer to aid in color coverage. In the first case, when applying light color paint to a darker wall color, you can maximize your color coverage by applying a white primer coat before applying your new paint. In the second case, when painting dark color paint onto a lighter wall color, maximize your color coverage by having your primer "tinted" the same color as your new paint. Many people are surprised to learn that this is possible. But the fact is, your local paint retailer will happily add any color they carry to any primer you want (thereby "tinting" it) for free!