Just be straightforward

Just tell them.

Just speak your mind

try to know their hobby and start to talk about their hobby.

Idk

It's different from one another, but do you feel the other person is holding some kinda feelings which wouldn't cause a conflict, or make the relationship awkward if he/she didn't like you back ?

Oc

Just do it

its spends on who this someone is that you like & just tell this someone how you feel