Stainless spokes: WD40 with 0000 steel wool. I may follow up w/chrome polish and a rag, but it's a lot of extra time with minor improvement.
Galvanized spokes: I avoid anything abrasive, and simply accept the dullness. I do clean with WD40, but with a shop rag or old towel.
Nipples: They often clean up with the WD40 and the 0000 steel wool. Otherwise, I leave them alone.
Eyelets: I remove rust with Rustoleum's Rust Remover and a toothbrush, then the WD40 and 0000 steel wool.
Rims: WD40 and 0000 steel wool to dissolve grit, then a rub down with a rag and WD40.
Brake Tracks: I rub slowly with mineral spirits, try to get as much of the brake pad residue to soften and clean off. Then WD40 and 0000 steel wool.

A lot of time spent on wheels can make a big improvement, but there is a point at which you can double the time spent and only see a little bit better results. Some hubs just don't have a good finish, period, and some others are amazing with the "khatful" treatment. The issue is knowing which are coated/plated well enough to hold up to polishing, and which just get worse.