I dont like to say much so I'll say it quick I hope
Small guys kick ass, dont let anyone tell you different
Your center is lower and reach shorter (great for in close fighting which is were you should be, attacking not letting up.
Longer limbs give that first intitial advantage when closing the gap and covering distance.
In warfare there is a saying, the faster unit decides the range of battle. There should not be blows traded! hit and hit and hit he will defend defend defend, thats the idea. Open him up. When he steps back you step matching him if he stumbles your mind should be sharp enough to follow him with no gap created and as his ass touches the ground your fist should be attached to his gums!
Longer reach suck for grappling except for levering chokes w legs or arms. And round kicks where the longer limb gives more centrifugal force. Long limbs are easy to get around and under and through.
Have the balls to attack with mushin "empty mind". Like in combat you gotta attack regardless if the enemy is firing at you unless you break contact and the get the hell out. Then again running is never an option in h2h. Your only option should be to win.
Get in close using your balls to get you there. Once there no prob attack legs with de ashi bari as you attack with punches or take down or whatever. He will be off balanced and vulnerable.
One Leg kick done properly will hurt your opponent in close. Many leg kicks done properly will render his close to immobile then manuever will take the day! Screen leg kicks with punches and crap like that, it's all pretty simple.
Balls will take you along way,That is what so many people lack.
Regarding grappling, Man it is too simple to get out of grappling, just don't play the game. Often times you can just stand right up and step back and smile. Of coarse there is 17 years NHB experience saying it is easy but seriously it is. There is alot more to all this than I am writing but remeber I'm trying to keep it short!!
I'm not going to explain who I am or what I do. Just keep it simple, direct, aggressive, and unrelenting. I've seen a little technique go along way in this manner.
PS: I'm not short, but do love training shortys.