Personally this is my technique:
After your first date, go back to the place you took your girl to and buy something that would make her reminisce of the experience she had with you.
For example: I took my ex-girlfriend to a Place called "Myers" and we sat down on a sofa and I put my arms around her and she put her head on my shoulders while watching people buy stuff. Then we looked at a couple buying a big fluffy stuffed chicken for their young daughter. My ex told me how much she hates Stuffed toys. (She's weird like that) Then I got the stuffed chicken and I taunted my ex with it. She got mad so I stopped and just gave her a kiss on the cheek. 2 Months later it was her b-day and surprise surprise....I got her the chicken. When she opened it she laughed really hard and punched my arm then gave me one of the best kisses I've ever had!
But here's another way:
During one of your conversations just ask her "So what make's your world go round besides me?" then she'll tell you all of her favourite things etc, remember what she says and then when it come's to her b-day just buy it.
For example:
I had a conversation with a girl that I was pursuing and i ask her the question above then she replied "Iron Chef....I love Iron Chef" just judging by the look in her eyes she absoulutely loves Iron Chef so I got her an Iron Chef DVD for her b-day.
See brother it's that simple.