The main attractions with girls are chocolates, jewelry and clothing. For your girlfriend buy a exquisite piece of jewelry like artificial jewelry, gold or silver jewelry, or diamond jewelry available in designs of bracelets, necklaces, rings, etc. it would be something over the roof top and will amaze her completely. Gift her a new cloth like top, shirt, skirt or an evening gown, depending on her clothing taste and make her wear that on her birthday. A bottle of Perfume, Attractive set of handkerchief, Books, snacks, body lotions, and gift certificates, her favorite CD, Teddy Bear, Show-piece and Portraits are some ever green girlfriend birthday gifts that are always admired and adored by girls. Gift baskets of chocolates and cookies or bath items make a perfect gift too. Include her favorite dark chocolates that she loves to have in the gourmet basket and sweet smelling soaps, shampoos and essential oils in her spa kit. Give her a day out at spa or any beauty relaxing saloon to pamper her and let her enjoy herself.
The whole point of buying girlfriend birthday gifts is not based on what you get her but it is the message of love that you portray with the present. She will see it as a measure of how well the relationship is going.