I tweak on this game a lot so, Here are some Techniques that I came up with.
-Study your opponents combos. Most players do the same combo in the same situation every time. It gets predictable. Example. A lot of guys do a step in Jab followed by a leg or body kick. Once you see the the step in jab coming, block the punch and flick the Right stick down, and you'll catch his kick. As the fight goes on just study his combos because most people don't mix it up very well.
-Time your own Combos. This is what I do when I challenge a person who always attempt to catch my punches and kicks. Be unpredicatable. Once you hit them with a strike, they are going to flick there right stick to counter your next strke. What I do is when I strike the other opponent, I wait for a split second before i strike again. It makes it harder for them to catch your punches and kicks.
-Play with stamina bar on. Makes it easier to submit people as well as knowing your own stamina so you don't get submitted.
-For Submissions and defending submission. If your character's strength stat is higher then your submission Stat, Mash the buttons. If your submission rating is higher then your strength, spin the stick.
-Muay thai clinch Whipping Knees. They Drain a lot of stamina, so try to avoid doing it right after another. You could get taken down and submitted.
-Getting someone off you when your on the bottom. A lot of guys take you down and hold there Right stick so you can't push them off. Kind of risky, but what I do is if I can't get them off, I just start punching them from the bottom. Maybe after 3 or 4 punches. He will eventually try something, he isn't just going to sit there and eat punches. Eventually he'll try to block, hit you back or advance his position, this where you have to hit a major transition first to get him off. Like I said its risky to punch from the bottom because you can get put in a worser position but it also helps in getting the guy off of you if you time it correctly.
-Reversing Transitions. This tip is really useful IMO. This is for when you are on the ground, doesn't matter if your on the top or bottom. A lot of people like to wait for you to do a transition, so they can block it and then they will attempt a transition on there own right after. A lot of people do this. What I do is i just do a transition so the other person can block it, and as soon as i see the animation of the transition end I flick the right stick. Chances are they they will be attempting there own transition by the time you flick the right stick, which lets your reverse them and end up a more dominant position. Also if you so happen to get mounted, and your opponent is still in the mount down position. He is going to try to move to mount up (offense.) Eventually he will get this position, so I don't even bother holding the right stick (unless the round is going to end soon.) I just wait till I see him trying to push to mount offense then I flick the right stick and hope I get the reversal(has to be quick tho.) Another one is if your mounted and you transition so he takes your back, as soon as he has your back chances are hes going to try and transition back to mount right away. Just flick the stick right as soon as he has your back and you have a good chance at reversing him.
Thats all I'm sharing =)