Any way to increase my speed?

Well I'm 6'5 300 lb defensive lineman and I run a 5.8 40, Which is slow. Is there anyway I could decrease that time? I'm only a sopre and I'm currently in a speed training cl that has to do with stretching, proper running technique and jumping. Is there any extra steps I can take to Push my self that extra inch to get faster? All help is greatly appreciated.