I'm kinda fresh as a first AC but i have never really had a shoot where i wasn't able to make the shots sharp.
My tips for you are:
* Skip all kinds of peaking, it just throws me off, not sure about other focus pullers out there but i usually just enhance the contrast in my monitor.
* If you pull wireless, i find it easier setting the focus motor setting set to right on the right side of the lens. So by pulling towards my body, the focus goes further away. And the opposite. Think of the movement of your fingers underneath the wheel and you wont pull the wrong direction by accident.
* Make sure to mark up a ring for each lens with distance. And don't be afraid to take marks if it's a hard pull. Tech-Rehearsals!
* If you have the chance, use a UDM-1 or cinetape for accurate focus measure in the monitor of your FIZ.
* If you're DOP is at T1.3 and on a gimbal freestyling, pray to the focus gods and trust your eyes for distance. Stick close to the camera.
But again, as mentioned above. Practice makes perfect. Maybe you can practice at a local rental house? They usually don't mind.
Hope this helps!