LEARN TO BLOCK. Being able to block everything you see is half the battle. All characters, with the exception of giants, in this game have great high/low mixups and the best characters have either special crossups (Tekkaman Blade, Polimar), or high priority/ ambigious air crossups (Tekkaman, Tekkaman Blade, Casshan w/ Friender etc...)
Learn other characters' most common blockstrings. Unlike most fighting games, most C normals and some B normals are unsafe on block, so watch out for them as that would be a perfect opportunity to counterattack.