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.
When painting with a roller, don't fill the tray more than one-third full. Also, load the entire roller with paint by rolling slowly down the tray and back, several times.
When painting, keep a damp rag handy to clean up as you go. It's much easier to clean paint that is still wet.
If you find bubbles or specks of some kind under new wallpaper, first cut an X pattern over the defect. If the problem is a speck, remove it with a tweezers or a utility knife. Then work seam adhesive into the cavity, squeeze out the excess, and seal the opening. For air bubbles you also can use a paste-injecting syringe found in paint and wallpaper departments.
When starring out, pre-dampen your brushes slightly before dipping into the paint. Slightly damp brushes apply paint more evenly. When working with latex paints, moisten with water: when applying oil-based paints, first dip them into paint thinner, then pat them with paper towels to remove excess thinner.
Paint walls from the top down. If you are using a roller, start by making a large "V" or "W" (3'x3'). Then fill in between the gaps, blending into your initial stokes. Always work from the unpainted into the painted area.
When painting from a paint can, give it a half turn periodically throughout the job. Dipping the brush into the can alternately on one side of the can and then the other automatically keeps the contents stirred at the surface and prevents a surface film from forming. Also occasionally sweep the tip of the brush back and forth through the paint, especially with a fast-drying latex.
When removing wall paper borders, use a hair dryer to loosen the glue.