Not really tweaks, just basic config for me. Tab stops at 4 spaces is fine, but definitely set translate_tabs_to_spaces to true if other editors like vi are going to be working with your files.
Also, fonts. Yeah, the third rail of text editor controversy.
"font_face": "DejaVu Sans Mono"
I tried 12, it was just too small for these ancient eyes (the default of 10 is ridiculous, who came up with that?). 14 was great, but required me to go full screen on a 20″ square monitor (real sysadmins use square monitors). So 13 was a compromise that I can live with.
And year, Sublime is fast, Really fast. Leaves Atom, and even VS Code, in the dust.