I have always wanted twins since I was a kid. When I was really young I always wished I had a twin myself. I think it came from being really good friends with twins at school (who were really close) and as I only ever had brothers and here were a pair of super close twin sisters, it made it seem amazing to me.
As I grew up I changed to wanting twins, I don't know why. Twins do run in my mother's side of the family in each generation with most recently my cousin (who was a twin herself) having twins last year. So that increases my chances. I'm still breastfeeding, which increases your chances to 12%. I'm also tall and this will be my fourth pregnancy. All factors that increase chances. I'm not holding my breath though
My dream would be to have fraternal boy/girl twins to bring our family up to two girls and two boys.
I took soy when we were TTC our daughter, not specifically to conceive twins, but because my ovulation was irregular and getting later each cycle and I'd heard soy could help - it did, I ovulated on CD13, but no twins.
I wouldn't take clomid unless prescribed, it can really mess up your cycles if they are normal and give you terrible cysts as well.