I have personally watched crushes grow into relationships. Some I have even helped along. When you think a boy likes you but are unsure, i will help you with a list of signs. Now not EVERY boy is exactly the same,  so I am going to categorize them. 

• Shy Boys: I have the most experience with these boys, so that's why I'm doing them first. Now they are complicated it took me a while to figure it out. 1: they look at everything but you when talking to you. 2: stare intensely when they think your not looking. 3: are known to have never asked out girls. 4: get mad when you seem distracted. 5: confuse you so they don't scare you off. Now 1 could possibly be a jerk move (to some people) but if you find out its unusual for this boy to do, then it is considered a sign. But shy boys will NOT ask you out I'm just gonna prepare you now.  If you really like them you'll have to make the first move and hope you read the signs right but most likely are right.
• "obvious" boys: Now these are also confusing especially to those who lack experience in flirting -well guys way of flirting-. 1: they are constantly making fun of you, but may stop if they see it isn't seen as cute then again some guys don't always realize it. 2: they are constantly bothering you but its because they're unsure how to get your attention any other way 3: you always see them notice you when your near 4: they steal your things and make you chase them to get it back. I used to think it was bullying but I was told by friends -who knew I despised them- that they admitted to liking me, when confronted by friends who didn't like they're ways. This one is sadly very common in the u.s -atleast in Tx- 
• Overly Attentive: These poor boys are usually friend zoned by us. And some lost hope and never end up confessing unless you ever did at some point. 1: they are always around you and talk to you a lot more then others. 2: they do things that most boys wouldn't 3: talk to you regularly and comfortably 3: they seem neverous at random times 4: they give you strange intense glances at times. 
• Sneaky boys: These guys are soooo good at hidding it is a shock when they suddenly spring it on you. 1: they're super chilled and seem to look at you. 2: try to talk to you regulaly by random means 3: look at you when you first walk in all the time 4: glance so quick you wonder if they did it but find you questioning it a lot 5: demand to know why you look at them a lot then laugh and start looking back more openly and playfully. I had a boy in my math class do this and he was soooo cute cx Now there are probably more but I'm lazy and this was already a lot its like 3 a.m and the only reason I did it was because my friend haruharu asked how you can tell, in a blog post and it inspired this post. I hope it helps but PLEASE I can not stress this next part any more. Before you do a thing talk to me here or in messaging. It'll be easier to give advice and help when you give first hand accounts! I also disclaim this as excat knowledge and any advice is yours to chose to listen to. So if you want advice or see a sign in these categories that you may be liked tell me in the comments below and I would love to confirm or help you figure out a way to confirm if its true or false. I hope this helped and you liked bye til next time!