As a complete novice I've been doing some work to try and get my head around the basic of using my DSLR to capture movie.

Focus - I find it impossible to focus when using a gimbal and am learning that an aperture of about f11 or f13 is pretty good for keeping the subject in focus. Problem is pretty much everything is in focus which isn't always to look I'm going for. Wider aperture and I find it very difficult to keep the subject in focus but I'll keep practicing.
When my camera is tripod mounted I find focussing so much easier.

Stability - keeping everything stable is harder than I had anticipated. Gimbal is great but I'm trying to perfect 'that walk.'
Again, on a tripod its great.

Think I'm managing frame rate OK but I need to keep this in mind as I easily forget when I concentrating on everything else.

Audio is awful, but for what I am doing at the moment I am using music and detaching the audio so its not a problem.

I'm enjoying learning something new, but I've a long way to go.
Enjoying the forum too.