It's generally better to avoid the dust in the first place, beforehand! Regular cleaning of your painting area (but not immediately before you paint) goes a long way to helping. I've also heard of folks "misting" their painting area with water from a squirt bottle (like a Windex sprayer) just beforehand, to help eliminate dust in the air.
Also, have someplace "safe" to leave the model as the paint cures. I've actually had more problems with dust when using enamels, I suppose due to the longer dry times.
AFTERwards though, a light buffing with a lint-free cloth will get some dust specks etc off the surface if they aren't cured in too bad. Or a light sanding if necessary. Another question I'd ask - WHAT are you painting. Obviously a high-gloss showroom fresh car model needs to be dust free. But if you're building a military vehicle that is going to be getting a dose of weathering, dust is not much of an issue.