Like many GMs, I've been running mostly on VTT for over a year now. I'm actually running more frequently online than I ever did in person (because it's easy to find games, convenient to get together, etc). But I am starting to consider how my style online is different in person, and which GMing muscles will need retraining.
For example, I tend to improvise less online. I have battlemaps at the ready, encounters already laid out. I don't want the players bored as I prepare an encounter, looking at a blank computer screen and disengaging from the game.
I have used more official modules. They're easier to setup when they're already on a VTT. Or even if they're not on the VTT, at least I'm not putting all the content on a VTT AND writing an adventure.
We are sticking with rules lite systems. Nobody in our group wants to learn a new system while not in person.
Character sheets are automated with the dice math already done. We don't even roll dice anymore.
I don't narrate areas as often. The map does most of the work. Players can ignore most of the description when they can see the placement of doors, hallways, and monsters on a grid.
My character voices and expressions are limited online. People seem to have difficulty understanding me using voice chat, so doing strange voices, whispers, screams, are just out of the question. Facial expressions and gestures are lost without a camera (and sometimes people aren't watching you even if you use a camera).
What are skills are you putting aside these days? What are some suggestions about retraining them?