I've had 2 professional painters tell me this:
Brushes - Purdy.
Rollers - cheap ones.
You never ever EVER wash a roller. It's a waste of time and water. Bag it between coats and then toss it at the end of the job.
Learn to cut in so you don't need to tape.
One trick I use for latex paint - get some FloTrol (sp?) and put a bit into the cup with your trim paint. It helps it lay flatter and get rid of brush marks. Thins the paint a bit. Gets that look of oil-based trim paint.
Sand all the corners before painting. Sharp edges = chipping.
No matter what the can tells you, two coats. TWO COATS! (More to make sure you covered everything than anything.)
I'm a big Ben Moore fan. Sherwin works just fine - used it for years. Not a fan of the Lowe's or Home dePot paint. Too thick!
The truth is you're the weak. And I'm the tyranny of evil men. But I'm tryin', Ringo. I'm tryin' real hard to be the shepherd.