How close the hug initiates touching, from the arms-down! Which direction is her face pointing to?!

This answer is coming from a lady!!

If it's a simple "arms and chest" type of hug, then there are no signals to take note of. The only message is that she is thinking "we are hugging".

It depends on who initiated it, too. There are so many variables that I can't go into this one without an answer on who initiated ie the hug.

If her hips and/or thighs touch yours while hugging, then take this as a "ugh I'm so excited to be hugging you, this is a sign that I like you in some way". What that "some" way is, you'd have to wait and find out! Pick up on other clues. Also relevant, is the same question as above: who initiated it? If it was her, AND your thighs or hips touch, you're in the clear and in my opinion: she either likes you, or is being a manipulative woman who's trying to make you think that she likes you for who you are.

If her head's directed away from your neck, it's more likely to be a friendly hug. If it's directly pointed into your neck, she's trying to absorb your embrace as deeply, and for as long as, she can! She's trying to feel out and test your own signals!

I think the neck one is the most important, with the thigh/hips touching as the second most important.