I personally use these - Vinyl Fever sleeves after reading a review of a bunch and trying a few, I prefer them over other external sleeves I've tried.

Internal sleeves, I like the Sleeve City Audiophile over their double version. Definitely the nicest I've come across so far. If your record came with a nice wax/rice paper lined inner sleeve great but not many do these days; paper ones go right in the trash and get switched out.

Outer sleeves are a preference but I'd definitely recommend using a nice inner sleeve.