Things that I've found mostly GMing over twenty years in no particular order:
1. Soundtracks - music can be a great tool not only for combat but to help build scenes (e.g. royal feast, holy temple etc.)
2. I certainly use voices and posture, gesture quite a bit for NPCs of note. My groups seem to enjoy it but I am also mindful of not going that route for every single NPC and still mostly focusing on what the players want out of the interaction rather than just me taking up all the time being a bit silly.
3. Narrative, description - avoid detailing combats as you take 30 hp or deal 10 damage. Embellish with some narrative touches (e.g. you deliver a reeling blow to the ogre, the thief's scimiatar cuts deeply into your flank for 10 hp)
4. Depends on your group but any campaign really depends on motivating the PCs and giving them something to care about (e.g. their hometown, building a pirate fleet). If the players are just grinding their way through a dungeon with no real reason to save for gaining XP any drama is likely to fall flat because there are no stakes.
I'm sure there's others but have to get going.
I find soundtracks to be very distracting overall. First of all there's the issue of setting them up, which detracts from gameplay; at their best they have a tendency to distance you emotionally from whatever's happening in the game. Life doesn't have a soundtrack, after all.
Life does, however, have sound effects. Soundscapes of, say, crickets and frogs and occasional nightbird noises can add to a "you-are-there" feel of a night encounter in a forest or swamp. Same for drippy cave noises for an underground/underdark campaign. Ocean waves help as well, if your encounter takes place near a beach or at sea. Background noises of human civilization are more likely to distract, though.