I was in the same situation, and frankly, the transition from online to live requires a real adjustment.
First thing: patience. The pace is very slow compared to online. You play 20-30
hands/hour max, so you have to learn to stay focused without getting bored or spewing.
Observe the players. Live, you have access to information you never had online: gestures, facial expressions, betting style, posture... Even if you're not an expert at
tells, just watching carefully can give you an edge.
Manage the atmosphere. Some talk a lot, others are ultra-slow, there's noise, pauses... It's a different atmosphere. The goal is to stay calm and in your own little world.
Simplify your game. Most live players are much less technical than online regs. So you don't need to
bluff like in 100NL Zoom. You play solid, value often, and let others make mistakes.
And finally: prepare yourself mentally and physically. Live is long. Bring water, eat lightly, take breaks... and above all, don't tilt if you're playing one hand every fifteen minutes.
If you've mastered online, you're already ahead of the curve. You just need to adapt to the pace and the human element.