You are in luck! I don't think you're grasping at straws... If you two have been hanging out as much as you say you have, it's gonna be rather easy to let him know how you feel. It can be difficult for teens to express feelings because we don't have a lot of experience doing so.
I'm a guy, so I'll just say how I would feel most comfortable with a girl telling me she likes me. I imagine it being a Saturday, she and I just went to the movies... we are walking back to the car and she says "I really enjoy spending time with you". That's perhaps the most subtle and easiest-on-the-ears way to tell someone you like them. I don't know how he would reply, but if he likes you back he will probably acknowledge that statement and say something back. Probably "me too" or something along those lines.
After that I suggest just going with your gut and saying what you want to say, more often than not it's easiest to just be honest and say what you feel.
I can't give too much more because I'm a guy, but yea.. that's my 'two cents.'