Buffing/wet sanding advice needed

My dart needs buffing or wet sanding and I was wondering where to start.
It's a non-metalic light blue with a dark blue top, no clear coat. No oxidation
to speak of but looks like starlings on prune juice graced it at one time. There are so many products on the market I don't really know where to
start. I'm not expecting miracles but don't want to leave it like it is or end
up with a bunch of swirls.

Also, the barn it was in had a small leak and there is a paint chip and rust
spot about half the size of a dime below the rear window. How should I
address the rust so I can apply some touch-up paint. Thanks.