Do you have a polisher?
Its normal to have some dust in a garage sprayed part. Most of them become invisible when polished however. If you have som 1500, then use it wet to nib the dust particles then polish the part to a shine...it might be all you have to do.
If the dust is visible like big visible lint or something like that then you will have to sand it out and probably re-clear.
You can sand, I would sand 800 wet, and re-clear any time after the clear coat has hardened. If you dont give it enough time the clear will wrinkle when you spray fresh clear on it. So wait at least 3 days before recoating and a week if you can. Naturally, the parts should be in a warm place (at least 70) for them to cure properly. Clear does not cure as fast in a cold garage.
What 88 was saying is that when you are painting, if you see a visible piece of lint in your clear, you can take some tweezers and pick it up while the clear is still wet. You then just give it a little spray to even it out. This will create a small dimple in the clear coat that will sand and polish easily. Its better than having a visible dust particle in the clear coat that requires a re-do...
A low speed polisher is a must when spraying in a garage and polishing is part of painting cars, that's how we generaly deal with small imperfections. Maybe that's the step you were missing.
My 2 cents worth...