Finishing tips needed

It seems like every time I work on a project, I get different tips on how to improve the finish of a project, better than the last time. Other than following the manufacture’s directions, which often don’t include these “tips” I was wondering if anyone had any good articles on finish procedures for the different type of finishes.

My current procedures:

(painted projects): I’ve been using Floetrol with a 4” roller

sand the project up to 220 grit
Prime and sand at 220 grit
first coat of paint with 220 grit
Second coat of paint

With this I sometimes feel like the finish project isn’t as smooth as it was prior to the las coat of paint, but I’ve never heard of sanding paint after a final coat (I’m to afraid of loosing the gloss).

Clear coats:

I’ll sand the project up to 220 grit
Spray multiple coats (at least 3)
I usually do no sand in between as I’ve been using the spray polyurethane and it says no sanding is needed as long as it’s less than 2 hours.

I have heard that if you brush it on you should use a foam brush and go with the grain the first coat and than against the grain the second one??

I’ve felt some bumps with this before and considered trying a 0000 steel whoop but never did.

Staining:

I don’t have a lot of experience with staining, but I’m guessing I would put the stain on, wait 5-10 minutes, rub it off and repeat after 24 hours for a darker look, followed by some polyacrylic????

Any help in this department would be much appreciated!