It depends. Some won't even show you a single sign but if you also like them, you may feel it.
But when they choose to show, they act shy when dealing with you, always want to sit close to you and don't wish you notice them, willing to help you out even when you don't really need it, not sure of what to say when talking to you, always looking at you and immediately looking away when you're about to notice, always trying to talk to you about nothing even though to them it's everything. There are many signs. If you're careful you'll notice it yourself ;-)
Ana06
