Please, it's so obvious that you have seen him so often. He also
sees you so often. If you don't approach him when he doesn't talk
to you, it's all the more unnatural.
You need to do it in such a casual way that it seems natural. But
first of all, you need to stop getting all flushed and excited
whenever you see him, otherwise, when you do approach him, you'll
definitely screw up.
Need some practical lessons? 
