dont look at the height, the builtness, or whatever that might bring you to say that you wont be able to beat or even be match againts your opponent. get in your fighting stance. relax, for he is just another opponent. let him kick you and just wait for an oppening and counter. if he kicks to high move in and unbalance him quickly and counter with punches quickly. i know in tkd they are teaching you alot of good kicks but only use the ones neccessary when sparring. remember stay relaxed and see those openings. its easy..... remember you are sparring to learn about yourself and to get a feel of fighting.