How do I get a super high gloss finish ...

I would start by removing all the rust and loose paint. Myself, I like to remove all the paint, sand, then primer for metal, and a high gloss spray paint from Rustoleum. You can use Rustoleum Rust Dissolver to remove the rust, and I use a soft brass wire brush and 000-0000 steel wool.

What hardware are you talking about?

Sand them down, wash them, spray paint them, and then put a clear gloss top coat on them :)

use citristrip to remove the paint, clean and spray paint with Rustoleums 2X for metal, apply two light coats and allow to dry in between.If using outside seal with a clear marine non yellowing varnish

I agree with Chas. Top coats come in different levels of shine. Like this: https://www.amazon.com/Minwax-Gloss-Wipe-Poly-U-S/dp/B009YNUT6Y/ref=pd_sbs_60_6?_encoding=UTF8&pd_rd_i=B009YNUT6Y&pd_rd_r=45N53QMJMP4MRYSF75BQ&pd_rd_w=vHNJS&pd_rd_wg=IY9KZ&psc=1&refRID=45N53QMJMP4MRYSF75BQ

Look for a high gloss finish on what you want to use for the top coat. Make sure it is clear and won't yellow over time.

Spray with a high gloss enamel spray paint.