unless your on fertility treatments it's normally all in the family genes. twins run rampant through both sides of my family, in fact my father and his 2nd wife had twins...and now i'm pregnant with twins, my greatgrandma was a twin, her mother was a twin and her grandmother was a twin. it really just depends on how many eggs your body releases at a time or if your fertalized egg splits or not. (the split one egg makes the identical twin while having an extra egg released and fertilized is fraternal twins)
I was pregant with twins (and lost them) and did not do IVF nor is there a family history on either side of it....More of a chance with IVF, but unless there are extenuating circumstances, they don't generally just do IVF on anyone.
i think it's more hereditery. also, if you see a fertility specialist and do IVF i'm sure your chances increase for having twins since you more than 1 embryo implanted. not very familiar with IVF. maybe someone else with more knowledge would be of better help in that area.
i'm not positive but i'm pretty sure you cannot just follow a pattern to get twins. i think it has something to do with the above. good luck trying though!!