Technics for having twins

There is a lot of stuff about this on the net here is what I found:

http://timesofindia.indiatimes.com/articleshow/1539606.cms
http://multiples.about.com/od/funfacts/tp/howtohavetwins.htm
http://multiples.about.com/cs/funfacts/a/oddsoftwins_2.htm

and a blog:

http://www.pregnancy-info.net/QA/answers-Natural_Ways_to_increase_chance_of_twins/

It's mostly one of the following that determines it:

Use of fertility drugs or going through fertility treatments such as IVF
Genetics (twinning runs in families)
Luck or a combination of factors that raise your chance of multiples like being somewhat overweight or over 35. I think there may also be a higher incidence of twins among mothers who have already given birth to several children.

Good luck,
Rachel
(mom of twins & of two babies who are a year apart)

I am not sure there are ways, other than hormones which are not recommended...

Well, I've heard that if you take clomid it can increase your chances up to a 10 %. I just started my cycle on clomid 100 mg days 2-7. (prescribed ofcourse). I hoping to conceive at least one baby, but two would be a great bonus. I'm 26 and I've had two pregnancy loss, both last year. Hope this could help

Dr. Alon, what study is used to tell if a woman on a fertility treatment has released any eggs? and, why is it that they use progesteron shots?