If you want to increase your chances of getting pregnant with twins, it’s important to understand how they are conceived.

There are two different types of twins:

Identical: formed when one egg is fertilised by one sperm. The egg then divides into two separate embryos. Identical twins might share a placenta and an amniotic sac or the twins might share a placenta and each have separate amniotic sacs. Genetically, the two babies are identical.
Non-identical: formed from two separate eggs, fertilised by two separate sperm. Non-identical twins have their own placenta and their own unique genetic composition. Factors that influence your chances of getting pregnant with twins are family history, Ethnicity, Several pregnancies and Age. Other factors are diet and Medication. Generally, Women who use fertility drugs and IVF are more likely to have multiples

The only one I'm aware of is the Chinese method. Check Google. I also find this help one here helpful https://www.huggies.com.au/childbirth/multiple-births/twins/how-to. All the best

Though gene and heredity has a major role to play when it comes to conceiving twins. Some couple also opt for IVF. U can see a fertility specialist for more info.