House Paint Tips Video
To keep the bristles on your paint brush clean while you are painting, dip the paint brush in water before starting, if you are using a latex or water based paint. This will keep the area near the handle moist and keeps the paint from drying out in that area.
Don't make the mistake of opening the paint can and dipping the brush into the can. This will drip paint into the lid groove. The paint will dry down in the groove and the lid will not seal properly. Instead pour some of the paint into an older, clean paint can. Then, clean the top of the paint can so the lid will seal properly. Use a paper towel, folded into a flat swab, and use it to reach down in the groove to remove any paint. This will ensure that the paint can lid will fit properly and the paint in the can won't dry out.
When trimming will another color paint, paint the large section or siding of house first. Don't worry if you get a little paint on the area to be painted that other color. That will actually help you get a better line when you cut in the other color.
These tips will help save your equipment and paint. And help give you that professional look.