To add to Bob's tips:

1. When you first start, keep your non-dominant hand on the surface and drill chuck.  Don't grip the screw or chuck, they need to spin freely, just keep your hand there to guide things.  This gives you control so you don't tip the screw over and jam the tip of your bit into the wall.  This also helps when you have an issue, you just pull the drill away and the screw falls into your hand.

2. If the bit starts to slip, STOP!  I've seen way too many people that try to go faster when the bit slips, and all that does is destroy both the bit and the screw.  Instead, get the bit reseated all the way in the screw and start again, slowly.

3. If you're installing a lot of screws and have a hard time with slipping, get an impact drill.  They tend to be small, and rather than torquing the screw in which is when the bit skips, they use the power of lots of small impacts, just as the auto repair shop uses on bolts.  They make screwing extremely easy, but they can't be used for other purposes, like drilling holes.