Summarize:

You don't have to change who you are or your natural style to impress him, just take pride in your appearance. Be well-groomed and clean at all times. Dress to accentuate your best features, whether it's your hair or your height. Don't go over the top with compliments. In passing, just casually mention that you like his shirt or how bright his smile is. He will be totally flattered that you even noticed him and felt compelled to actually say something. Guys like to feel useful and needed so enlist his assistance with something, anything! Whether a big request or small, he'll jump at the chance to lend his skills or time. It can be anything like passing a book to, handing you a straw or giving you directions. Profess your gratitude and really make him feel good about what he just did. Use the face time to further the conversation. If you want him to spot you, it's best to avoid standing at the back of the room (unless that's where he is) or hiding in the corner. Keep your head up and arms uncrossed. Instead of "hiding," stand in the middle of the pack. For example, if you're standing with a group but behind everyone, subtly make your way to the center instead. Our eyes are naturally drawn to the center of an image so let the crew work as a frame for you. An appealing look is one where the eyes look round and full. You can create this look naturally by being mindful of your gaze. You can also do this by arching your eyebrows. Whatever you do, maintain a soft look on your face to show that you are warm and friendly. If you catch his eye, offer a smirk. Nothing says unapproachable like staring at your cell phone so put it down.
Look your best. Compliment him. Ask for help. Watch your body language. Watch your facial expressions.