I’ve been a fan of the shirt half tuck for quite a while, as it’s chic, cool, and adds an edge that’s not so typical. Theres also something about an unfused yet structured tailored look, thats polished and relaxed at the same time. Here’s the rules I adhere to:

Never wear a belt – I want the focus to go towards the style and how its a deconstructed look.
When wearing a button down I tuck in the center creating an even clean line.
If I’m wearing a jersey of a tee, I do the side tuck, with some looseness hanging over the edge. This creates a casual relaxed feel.
I never tuck in the back. Now if the shirt is over sized, I make sure the edges are tucked in so it doesn’t make me look any bigger around the waist.