I think your chances sound pretty good already since they run in your family and you are 36. The only twins in my family were my grandmother's siblings and nothing until me. You might want to get the book Having Twins. I think it is a wonderful book and she believes that some women can will themselves to release 2 eggs. I didn't read much about it since I was already pregnant at the time, but I would look into. What do you have to lose, really? I think there can be power in that stuff. I spoke to my body everyday during my pregnancy, saying positive things like we were going to make it to 40 weeks, have no complications, etc. It might sound goofy, but it surely isn't going to hurt anything.
I hope you get your twins!! I desperately wanted twins, too, and I got them. Even before I was pregnant, I would read about breastfeeding and co-sleeping with twins and I would think to myself that I would be a good twin mom.
That said, twins are more work than I could ever imagine. They are certainly not twice the work, it is more like 4 times the work. I had severe PPD and barely survived that first year but I would do it all over in a heartbeat.