I have a rather odd history in marital arts so its hard for me to tell you what to do. work on your foot work for one. if he is a boxer the last thing you want to do is trade punches with him. Most street fighter arn't conditioned to take a leg kick a good leg kick does allot of damage. Also learn to throw and good front kick and push kick as the reach of your legs are better than the reach of his arms. if you keep a guy at bay long enough often times they will get frustrated and rush in or throw a big uncontrolled punch making it easy for you to counter. Dont fall in to too much of a patter though.
However this is easy for me to say because i took tai chi and Ba Gua where id developed a stance and foot work that a majority of fighters would not know how to react to. Also I took TKD and Karate where I have developed a strong front kick.
I dont recommend this for you but i know what I would do is throw some kicks with my left leg to get him watching it then i would raise my leg like I was going to kick but then come around with a right spinning back kick or spinning side kick. it would take allot of training for you to be able to do this effectively though.