When passing guard, pull their arm between their legs. Pull their arm up when mounting
Triangle choke: They try to break out of your guard. They have their right hand on your chest, left arm under your right leg, lifting it up. Bad position! Never have one in, one out (have both in or both out).
Always keep your feet on them, have all four limbs working for you. Left hand grabs their right tricep, your right hand grabs their right lapel. Put your feet on their hips. Swivel to your right, trying to get perpendicular. Put your knee joint on their neck, put it down. Don't have your lower leg on their back at all. Hook it under the knee of your left leg, then bend your left leg down. Reposition if you have to, adjusting from the inside (not grabbing your own foot). Keep your knees tight together, pull down on their head *. Their neck is crushed in between your knee, use leverage. Bring your butt down, resist urge to lift it. Otherwise, they can stand up. Hips low, pull forward on their head. They have one arm on the other side of their neck.
To armbar (from * above): If the choke isn't working, can go into the armbar. Keeping your knees tight to their head, slide your right leg over their head. Do not separate your knees or else they can push one down and escape. Pull their arm down to your chest, lift up your hips. Pretend you are doing one of those leg raises (both feet in air, push up legs).
Practice forward and backward rolls. Do the squiggly leg thing (spin legs in opposite directions). Practice turning in a circle on your back. Then move laterally on your back. Then get up on shoulders and move forward/backward. Practice hip-outs.