What should i do? What should i say? HELP!!?

ok so i like this guy...he is in 7th grade...and i am in 8th grade. i don't see him that much in the halls. i only see him before am homeroom and before pm homeroom and we have no cles together NOTHING not even lunch because we are in different grades! i have said hi to him 2 times before and the first time he waved and the second time he said hi. how can i get the nerve to start an actual conversation rather than just a hey. and does anyone have ideas of what i can say to him so that its not weird or awkward?