If they try to stand close to you at parties, or sits next to you at lunch, chances are they have a major crush on you.
Perhaps you have picked up on some of them… or not.
For example, he habitually asks you to chat, and those who chat and find topics are always with him, then he must like you.
We all need someone to talk to once in a while.
Try a small joke and see if she laughs way too much -- this may mean that she has feelings for you.
If she's the same way with everyone, then it's just part of her personality.
Or possibly take things a step further and share a bed? She seems a little embarrassed at having been caught.
Notice if they follow you on social media.