I agree, stamina is worth targeting. The longer you can stay in the match, the better chance you'll have to win, and the more XPs you will receive. It will also allow you to hit stronger moves late in the match, from what I understand. I'd try to boost both my stamina and stamina reducer if I were you.
Also, block and dodge could be increased as Speedy Boy says, but from what I understand, it's best to focus on one of those. What I mean is, put a lot of Technique points into block, and save your speed points for other categories. Or vice versa. Apparently it is more effective to have 40 block and 0 dodge than it is to have 20 block and 20 dodge, so I'd say focus on one, and forget about the other.
I'd try to boost that adrenaline gain some, as well. The higher you get that stat, the bigger finisher you will be able to use, which will pick up some wins for you in matches where you are currently losing in close fights.