Mount Game
From mount, I feel like I’ve got a complete suite of options. Jesse the Blue showed me his kimura from mount, which I can use if the guy has his arm down by his side—for example, if he is blocking me from bringing my knees up deep under his arms. Jesse pointed out how even if you get bumped, if you’ve got the kimura locked in you’ll still be in good shape. Ideally, if he’s still on his back when you’re sinking in the kimura, then you’ll want to step over his head (stepping over to the kimura side) and slowly crank the kimura back.
My other options are the arm triangle, keylock/Americana, cross choke and armbar suite. The arm triangle is ideal if he keeps his arms up high to defend against the kimura or the choke. The choke is, of course, a good way to bring his arms into play for an armbar or even a straight keylock. The armbar is a good variation if he is fighting off the arm triangle and his arm is just waving out there.
I need to remember that mount can be tricky to maintain. Be ready to switch into the "technical mount" or S-mount and work the armbar/choke combination from there.
Guard Game
This is by far my weakest area. I’m having a hard time moving in the guard, and still don’t really "get" the concept of stepping on the hip. Actually, I think I’m starting to get it conceptually. But I haven’t been able to actually apply any of it in a real sparring situation.
From the guard, you must break your opponent’s posture.
Given the way that most guys are fighting me—with incredibly solid posture and taking few risks to pass my guard—this is vitally important. The most effective way to break the posture is—as Saulo Ribeiro says—to change the angle. Stepping on the hip is all about changing the angle of your body and the angle of your attack.
If I step on the hip with my left foot and pivot my body to my right, then I might be able:
--to trap his arm on my right side, hook my right leg under his armpit and apply an omoplata.
--to armbar the arm on my left side, by pulling that arm toward me as I pivot, underhooking him with my right leg, and swinging my left leg over his head
--to get better leverage to cross choke by grabbing the opposite collar with my right hand and the opposite shoulder with my left, turning my palms up as much as possible, and curling my wrists and bringing them toward my chest
--to trap his arm on my right side, reach over with my left arm and apply a kimura.
Stepping on the hip also creates distance, perhaps to stand up, or to switch to an open guard like the butterfly or spider guard. Right now, those two guards are more "sweeping" guards than attack guards. But being able to switch from closed to open guards is a skill worth developing.
Watching some top fighters in the guard, it also seems important to be able to launch guard attacks from both sides—-i.e., stepping on both hips and attacking both arms/shoulders. Again, you want to break the posture, to get him to commit to one side or the other. You can’t do that if you only attack one side.