Use the right solvent to clean up paint equipment. Check the paint can label. Generally use a mild detergent solution for water-based paints, mineral spirits for alkyd enamels, mineral spirits or turpentine for oil paints, alcohol for shellac, and mineral spirits for varnish. When you are reusing solvent for cleaning equipment, occasionally rub some between your fingers. When it begins to feel sticky, dispose of properly.
Always store paint in its original container, with the label intact. This will help you properly identify rise color and type of paint when you go to use it again. If key information is concealed by paint drippings, write down the brand, manufacturer’s code, color, gloss level and type of paint on a strip of masking tape and affix it to the side of the can before you put it away.
Like tile, most paint will differ slightly in each lot produced. If you plan to use the same color thoughout your house, it's a good idea to purchase as much paint as you can at one time. This will avoid any deviations in the paint color and save you an extra trip to the store.
When using latex be sure that the temperature is above 50 degrees F. It is difficult for latex to form a film at lower temperatures. With solvent-borne paint, be sure the temperature is at least 5 degrees above the dew point. If it isn't, water may condense on the surface as it cools while the solvent evaporates, causing an uneven blushing effect.
Even if your paint was mixed at the store, stir it thoroughly before each use. If it sits for a while during painting, it is best to give it a quick stir periodically.
When using a paint pad, apply the paint with long, straight strokes, all in the same direction. Do not pull the pad back over the painted area. Also, be aware that paint pads have a tendency to leave lap marks if you do not feather the paint carefully where one stroke meets another.
To be certain you'll have touch up paint you will want to buy a gallon or so extra and be sure to have the salesperson write down the exact ingredients of the paint you choose. Luckily, there are machines available which can analyze a chip of paint but, there's that old saying about an ounce of prevention...it could save you from buying gallons later.
Most exterior paints will cover about 400 square feet per gallon for one coat. But adjust for waste factors like the type of surface and equipment used. If the surface is rough or porous, add 20% to the total gallons figured. If siding is narrow (4 to 5 in.), add 10%. If on a corrugated surface, add 33%. Also add on a 10% waste factor if using brushes or rollers, add 20% for airless paint sprayers, and add about 40% for air paint sprayers.
To save on expensive solvent, try this when cleaning up brushes. Find two cans with plastic lids, one can smaller and one larger. Pour the proper solvent in the smaller can to clean the brush. After cleaning, pour the used solvent into the larger can. The sediments will settle out in a day or two so you can reuse the clear solvent that will remain on top.
If you want to re-use a roller cover on several paintjobs, it is best to start with the lightest color, then work in gradually darker colors, following each job with a thorough cleansing of the cover.