Him going to you for help when Seven gives him a lesson to do regarding emotions/social skills and you would always be willing to help him understand emotions better and offering to help
You always being so impressed by his intellect and knowledge; asking him about the things he's learned and the science he's interested in
Him being so appreciative of you being there for him, though not able to show you how he feels properly
You helping him through the guilt of having been a borg, and comforting him whenever he's upset about that or about anything, really
Him always trying to show you how much he cares about you with little gestures that Seven recommends; asking you to hang out more, bringing you snacks, taking you to the holodeck, etc.
You developing feelings for him, but not wanting to tell him because of him struggling enough with emotions as it is
You having to hide your true feelings from him all the time, though it'd be hard when you blush near him:
"Are you warm, Y/N?"
"No, why?"
"Your cheeks are pink."
"Oh... uh, yeah, I guess I am kind of warm."
Him talking to the doctor about how your cheeks have been really pink lately and how your pupils dilate when he's near you
The doctor having to explain to him that those are signs of you having a crush on him
After hearing that, Icheb realizing he might like you as more than a friend so he'd go to Seven for advice, and even ask Tom for advice, too
Icheb trying to admit to you how he feels, but he struggles so much and stresses over it. He isn't the best with emotions and feelings to begin with, so him trying to admit to you that he likes you would be a nightmare for him
Him asking Tom for help; so basically he'd ask Tom to ask you out for him. Tom would probably plan the date, too. Tom's pretty much Icheb's wingman, though Icheb would get very confused when Tom used that term to him
You'd say yes, of course, and it would be an amazing date leaving both of you eager for another