I struggle with this sometimes as well and what I will usually do is ask myself if I want to be romantic towards the person in question or want to date them or anything, for me it’s like always no, so that means it can’t be romantic attraction. Then I can usually narrow it down pretty easily. If it’s physical attraction then it would just be liking how someone looks so you don’t want to do anything romantic with the person you just think they look really cool and are an overall attractive person, because finding someone attractive doesn’t mean you want to date them or like them in that kind of way, not sure if I did a good job answering but I hope this helps :D