Preschooler with Behavioral Issues

I just started working at a preschool and one of my students has some abnormal behavioral issues. Just defiance, ignoring, screaming, arguing, etc. Things outside the norm of the average pre-k student. What can I do to help him cope during school? I hate to punish him and stuff so I'm looking for alternative solutions to change the behavior rather than punish and see no change. He feeds off of all sorts of attention, and acts even worse when ignored. Opinions?