If you get a run or dust in the clear, sand that spot down until its gone. But when your done with your last coat of clear, start with 600 wet until 2000, but in your case 1500. Start with 600, and stop once all the paint appears dull and flat. Then sand with 800 until the scratches from the previous grit is gone. And keep doing that. Then when you reach 1500, you can buy 3M Fine Cut Rubbing Compound. You can rub that in with a cotton cloth. When your done with the fine cut rubbing compound, get 3M Finesse It II. Rub that in and your paint will look like glass!