I didn't read the link posted by MinnFlyer and it probably covers this, but in case it doesn't, I'll just add my two cents:

ALWAYS vacuum the model prior to covering. Don't just use a tac rag because it won't get all the dust off. The covering will not stay down if you cover over a dusty model.

If you have an air compressor, then this is the order to go in:

1) Sand model (repeat until three times after you think you've sanded enough. )

2) Blow dust from model.

3) Vacuum model.

4) If you find something that needs to be fixed, fix it and return to step 1.

5) Start covering.

Good luck. I went with greenboot's option 3 as well. Unfortunately, it did kill me, but as luck would have it I'm immortal, so I lived to tell about it and try again.