It depends stage of pregnancy. For pregnancy of less than 12 weeks, medicines like cytotec can work. But after 12 weeks D and C can be recommended.
It's extremely dangerous to try and induce a miscarriage on your own. If you are sure you want to have a termination, you need to make an appointment with your doctor and have the procedure carried out safely. If there are problems with going to your doctor about this, you should visit a special centre such as the Brooke advisory centre - they can also give you online advice and contacts wherever you are.
You could kill yoursel if you do this without medical help