Three steps to a perfect drywall paint job.

1. Level 5 drywall finish; very uncommon and three times the price of a normal drywall job.

2. Adequate primer buildup and application.

3. Skillful painters, quality tools, and equipment.

A level five finish is the best possible finish you can apply to standard drywall. To apply a level five finish you perform all the normal processes of finishing drywall; Pre fill coat, tape coat, bed coat or fill coat, skim coat or final coat and then sand. That's a level 4 finish. A level five finish simple put is a coat of drywall compound ( a harder compound than finish compound) on all surface of the drywall from corner to corner from floor to ceiling as well as the ceiling this give you a nice consistent surface and the best possible finish. Read complete perfect wall finish article.