Why do girls do this?

If its a girl who you see regularly and have not spoken to her then shes into you if shes making eye contact. What other signals is she giving you?
Girls dont make eye contact if there suspicious. They avoid your gaze and would stay away from you.

She pretends to be on a phonecall but at the same time makes intense eye contact with me. I get the impression shes trying to show shes popular. She comes across as shy and awkward.

If youve nevervapproached her before and shes doing this I would say it sounds like shes interested and wants you to approach her.

I did approach her. She responded friendly not dismissive. I decided not to push as it wasnt the right time.

Did she seem open to talk? Did you ask her the basics?

I didnt ask her the basics just asked her a question to see how shed respond and she didnt say no she gave a 'decent' response. I could have pushed for a convo but it just wasnt the right time.
I just cant tell if shes interested or just being shy. Shes seen me around enough times to know i might approach her and im sure she knows i like her. When she saw me she made a point of making eye contact but at the same time pretended to be on a phonecall.
If she didnt want me to approach her she would have avoided me and wouldnt make eye contact right?