Any advice on learning slide guitar? It looks so easy, then I try it and it sounds like a swarm of killer bees are coming out of my amp. I love Derek Trucks style. I'd also like to use standard tuning and not an open tuning, but if it makes it easier I'll just tune up my other guitar to an open tuning. I also know I should be on top of the fret wire and not behind it.
Maybe we need a "sticky"... I feel I've written a similar post a dozen times.

Anyway... Open tunings are best for acompaniment; for playing delta blues and similar tunes as you sing. You get chords that way, you see.
You can do fine solo playing as well in open tunings, of course.

With standard tuning, you normally play single-note lines as a lead player might, only using the slide. Duane Allman (a big influence on Trucks) did a lot of playing this way, but used open tunings as well.

Basics... You should have a dedicated slide guitar, as the action really should be rather high. This to avoid whacking your frets all the time with the slide. The main thing is the action at the nut, so a simple replacement with a higher blank would do.
You should be able to fret notes as well, as a lot of slide technique involves both fretted notes and chords and slide work.
Heavier strings are better.
Muting is perhaps the most important technique to learn; muting the strings behind the slide will prevent a lot of extraneous noise. Most players wear the slide on their pinkie and mute with the index.
Work on vibrato, sliding acurately from note to note, playing individual notes cleanly, and "attacking" the string smoothly rather than slamming the slide down.
Advanced techniques include fretting notes behind the slide and also angling the slide to get different chordal effects.
There's tons of instructional material on YouTube.