Don't worry, you are the painter, worst case scenario you paint a little more.
I step sand, use 1000, 1500, and then I use the 3000 pad that 3M makes, I cover all the edges with tape so I don't cut them, I use the squeegee that 3M makes, then I use the 3M system through to the wax. Never buff a car in the sun, you will burn it, put a little dish soap in your wet sand water, use a spray bottle with just a touch of dish soap, 2 drops and mist your buff. I use beef cloth or baby diapers to hand buff and polish, and a shamwow or a terry to clean it up. Keep in mind that a lot of polish products have wax in them to fill in the fine line scratches, you would rather not use those products for your initial buff out. In two weeks when the wax evaporates you'll be all crazy cause the fine lines will be back. Wash it well and apply another wax coat before you buff it again.