How to act around your crush is a difficult question to answer because so many different people have so many different opinions. Firstly i think i should point out that i was asked to do this by quite a few people. Here is what i would do:
1. Get to know him/her: become friends with your crush and always do your hair well if your a girl. be sure to let your crush know that you want to be friends with him and i assure you they will eventually fall for you.
2. Create a love/hate realationship with your crush: this is a good way to get to know the person and to get to know them.
3. Mention whats going on in other people love life to them (if your at school mention if other people have started dating): at my school we have a French Dinner comming up with a Marist Brothers school, two people have just started dating and I told my crush: "He's probably just trying to make sure he doesn't lose her to some Marist boy who she's only met once." trust me this will work and has worked for a while.
4. THIS IS THE MOST IMPORTANT ONE!!! If you have the confidence you may as well get him/her alone and tell them you like them. but be suddle don't say something like "Hey guess what I like you!!" and then try and kiss them. wait for their answer and if they like you too just smile and go from there.
5. What's Happend With me is that I'm getting to know him and have been friends with him for 3 years now but we are both going to different schools next year so I am trying to get some confidence to tell him I like him. the years almost over and I think he likes me too if you have any advice you wanna add feel free to comment it and i can add it in or if you have any advice for me please comment it and i promise i will read it and learn even if it is just encouragement!