How will her knowing I like her make her feel differently??

People like to be liked.

Telling someone I liked them was being vulnerable, and vulnerability demonstrates strength, which is attractive.

The question that has worked best for me:

"How am I making them feel? And am I satisfied with how I am making them feel?"

Usually this pushes me to take risks: often it means being honest about how esteem them while giving them plenty of space.

I have felt the best when I had a not-so-secret admirer who was willing to spend time with me without demanding a commitment too early. So I try to give that same experience to the people I care the most about.