Proper fitting suit with proper tie, not a pencil skinny tie.
European (slim) or American (looser), doesn't really matter, IMO.
Get something that looks like its yours. Not your dad's.
Suit doesn't have to be $500 or $1000. If it fits, and doesn't look like H&M "suits", you'll be fine.
Zara, Express, and other "fashion" stores will be pushing it.
Get a wool suit, not some polyester crap.
Have proper sleeve lengths with proper shoulder fitment.
I'm getting a suit from Macy's and getting it altered. All in all, 2 piece suit will probably end up being somewhere shy of $500. Vest? maybe.
Navy, Gray, Brown(?), and other darker colors seem to be fine.
Black demands too much attention/authority, that's why black isn't worn to interviews.
Checklist:
proper fit suit, belt and shoes.
proper/discrete watch.
don't look like you just woke up (hair).
proper shirt and tie combo (learn to tie your tie).
socks. save the pink blue lavender argyle sock for a casual night out. stick with a solid color that doesn't clash with the suit.