Soap sand it with #1500. #1000 if it's real "lumpy". Stay completely off the edges, just sand up to them, but not on them. Go over the whole thing with #1500, then see what you've got. If there are still bad areas, go over them again til they're smooth. Rinse often. The "soap" refers to just that, add some dawn dish soap to your clean sanding water, use clear, clean water to rinse with, often. Stay off the edges. When it's all done and you are satisfied that it is as smooth as you want or can get it, rinse it good. Now you are ready for the work. Get some fine machine buffing compound and start buffing. You have to use a buffer, not by hand. Use clean water with the compound. Sart with a little compound, then add water while you buff. Don't let the compound dry out, keep adding water, til you are buffing with water alone. Don't stay in one spot, keep moving or you stand a chance of "burning" the finish. Soap sanding and buffing can be considered an art form, when properly executed, but has screwed up more than one paint job when tried by a novice. There are also very few show quality paint jobs that have not gone through the process.
Just take your time and don't try to do too much all at once. If you get it right, you will be very pleased with the results. If you get it wrong, you will be pricing paint jobs. Hard if not impossible to give adequate instructions with just words, it's one of those things you have to be shown, or learn through experience.
Good luck and let us know how it turns out.
Did I mention to stay off the edges and rinse often with clean water while you're sanding?
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Have a good one!
