[Frodo]

Good suggestions. Here are some more:

1) In high guard - either gi or no-gi, I always make sure one leg is over one shoulder and I had wrist control of that arm.

2) If you get stacked, try a sweep. Either a star sweep, pedulum sweep, armbar sweep, or just toppling him over like tomoenage would work. To avoid getting stacked, walk your hips away from him while keeping a good lock in high guard. That will stretch him out.

3) Pulling out is a risk, but if you go for a sub immediately after establishing high guard, it will be less of a risk. Don't hesitate!

4) The santina is a cool, simple submission. You simply pin his elbow to your hip and pull his arm the other direction. Works the same as ude garami, but without the arm entanglement.