I know I personally had trouble figuring out if a guy is interested in me or not. Well, I should say ones you like because women know when a guy is trying TOO hard.
I came across this article about 5 Ways To Know If A Guy Is Interested In You.
1.) Read his body language: Is he leaning in while you talk? Whether it's a subtle lean-in, or even a full court press, proximity to you is a yes!
2.) Gauge his eye contact: If he is into you, he'll hold his gaze steady. Make sure you make eye contact back to let him know you are interested too!
3.) Does he want to be near you? If you are on a date and find that he is taking every opportunity to touch you, whether it be a brush on your knee, or even your elbow, he probably likes you.
4.) He is mirroring you: When a man mirrors your actions, it is definitely subconscious, and a strong sign that is interested in you. Notice that he is copying your gestures at the table.
5.) He wants to relate to you: Men and women have to find common ground between them, so often if a man is interested in you, he will WANT to find more ways to relate to you. He will also share things with you -- his experiences, his opinions. In his way, he can check in to see if you are compatible and find out if you are a match.