Do you think a girls personality has anything to do with her looks?

The first thing I try and do is realize that one's appearance isn't tied to one's beliefs, personality, or etc. (male or female)

If you don't know or observe a person long enough, their looks alone will tell you nothing about them when it comes to their personality.

And while people judge on first impression/looks, it's best to stop yourself and re-evaluate the fact that appearance and personality are not 1:1. Appearance alone tells little & you might be too biased in the assumption of all character traits based only on looks.

If you want to get an air of someone or look more in to a person as a whole, you'd best spend time around/with them or read their works/literature/opinions/etc. and that can tell you more of them than their appearance alone would any time.

For example, here is a good place you can easily learn about people without knowing what they look like, whereas in most situations it seems to work more the other way around -- i.e., knowing what they look like without knowing much else (like with strangers).

Observe and learn > just look and learn is how I see it. You have to disentangle impression with a person's actions, interests, etc. in order to see a person and their personality as separate concepts -- not just a person with your impression of their personality preconceived.

Yes, sometimes. Looks often influence the way you are treated by others and how you feel about yourself and, in turn, the way you treat and feel about others. That's pretty basic knowledge.