There are various ways... Sticking your fingers down your throat. Ipecac is usually used to induce vomiting in case you have mistakenly swallowed poison. If you don't have Ipecac, another way to induce vomiting is to mix table salt with water, and then drink the solution. If vomiting does not occur, you can follow with a glass of room temperature soda or other carbonated beverage.
it depends on your body. some people can vomit on will and others like me do not have a gag reflex. unless you are sick and vomit naturally, making yourself vomit is very unhealthy and dangerous because you can unintentionally give your self a case of bulimia
The simplest way is to drink some Syrup of Ipecac (if you can still get it). This medicine is used for emergency purposes (only) and must not be used regularly. Regular use will cause heart failure and many other complications.
If you're doing this to harm yourself in any way, then I'd feel like I wasn't giving you good advice if I told you how...
umm i would like to answer this question but if your going to do this for self harm i will be unable to help.
I hope you don't have anorexia, a friend of mine's older sister did and she died from it.
Better will guide you a family doctor.