my girlfriend is always complaining about something. whether its talking on the phone or hanging out together she is always upset at me for something. how can i help her stop getting frustrated with me??

totally understand bro, it;s like there is no pleasing or doing anything right, then when trying to have a normal conversation with here she goes off on these tangents that dont even make any sense.
i know it is a always hard to actually do it, but i think that it it is best to fins a girl that isnt so prone to fighting, its like the proverb says, better to live on the corner of the roof rather than live with a quarelsome wife, and dog your girl is quarelsom...at least for now she is...

are you two long distance? what are some of the things she gets upset about? just curious...look forward to hearing back

She may not just be innately quarrelsome. As a female I can vouch for this, there may be something larger that she is upset with and so it is effecting her whole attitude towards you and the relationship. It could even be something outside of your relationship, you need to ask her. Ask her why she never seems to be happy about anything, she may not even realize how her behavior is coming across. As with most things in a relationship, you need to talk to her about it. Based on the behavior you've described it seems she might take what you say the wrong way and find yet another thing to complain about. I would start by letting her know how her complaining is making you feel. Also, if she doesn't try to change let her find somebody else but try to work things out first, you got together for a reason, maybe she needs to be reminded what that reason is.