Trial 21:
Make sure you DO NOT BACK UP AT ALL when doing the standing jab. If you move even so much as one pixel backwards, the crouching strong will whiff.
Trial 22:
Be good at links? Lol, it's a pretty straight forward trial with tight timing windows. Dash Straight -> Super is pretty easy, hold back during the combo, then press forward+punch, back, forward+punch
Trial 23:
This combines two of Balrog's fundamental combos - EX Dash Upper follow ups, and Buffalo Ultra. If you're having issues getting this down, try both of those concepts separately until you're comfortable doing both in the same string.
Trial 24:
The same as Trial 23, but with a jump-in and a harder link. If you get 23, you should get this no problem.