Ignore jokes made at your girlfriend's expense. Although this may sound reasonably simple, it can be challenging to deliberately avoid laughing when you see other people amused by a joke. Although it’s not always appropriate to confront people who make these jibes, if you laugh it reinforces their behavior and increases their tendency to make your girlfriend the butt of their jokes. Also, your girlfriend may feel betrayed if she learns that you laughed along with people belittling her.
Demonstrate love by protecting her from emotional pain and strengthening her without any expectation of return, suggests Chuck T. Falcon in "Judging Boyfriends and True Love" on his website. Offer a hug when you know her feelings are hurt without hoping it will turn sexual. Touch her gently, patting her on the back and assure her of your love.
Support her ideas and projects, even if they are criticized by her peers. At the end of the day, she should feel that you support her new ventures. Encourage her to remain confident in her own abilities and point out areas where you feel she excels. You do not need to conceal any negative feelings; rather focus on complimenting the positive aspects of whatever she’s trying to do.
Promote her accomplishments. If your girlfriend is modest about her achievements, mention them in social situations when an appropriate opportunity arises. For example: “It’s funny you should mention amateur theater -- Kirsty recently directed a fantastic production of 'The Elephant Man.' "
Be a confidant. Occasionally, we all feel frustrated by certain people in our lives, and it means a lot when your partner listens to your stories and offers support. Allows her an opportunity to talk about her personal frustrations and provide emotional support. Listen actively and take care to avoid responding with your opinions of how she should fix things.