I've done small parts at home, and all I can say is:

1) Read the instructions 3 times, and be sure you understand them.  If anything is unclear, the folks at Brownell's will be glad to help.

2) Go through a "dry run" first to familiarize yourself with the mechanics of the process, and to make sure your equipment is GTG.  Your first item should be something with which you can afford to make a mistake.

3) Some surfaces don't like being parked, such as the bores of barrels and sear/trigger engagement points.

4) The finer the beads used in bead-blasting, the less damage to any engravings, serial numbers, and so forth.  

5) Last but not least, preparation is everything.  Parking is not hard to do if you have the right equipment, but it is pretty unforgiving if you cut corners.

This might be a good time to mention that a good epoxy paint, such as Brownell's Aluma-Hyde II, applied over a fresh, de-greased Park job is a killer finish in terms of water resistance, durability, and low cost.  Such a finish rivals much more expensive send-away jobs if done right.  The only caveat about painting over Park is that Parking does change the parts' dimensions minutely, and adding paint contributes to dimensional build-up.  Some pre-planning and judgment is required, and most paint-over-park applications are on parts of the firearm that do not involve very close tolerances.  That said, it is a wonderful finish, as a fresh park finish really grabs the paint, and epoxy paint is tough as nails.