There are tons of options when it comes to eloping. Do your research. Make sure you have all the necessary documents and ask if there's a waiting period before marriage. Pick your country wisely. While it might be great to elope to a foreign country, if you ever need more copies of your marriage certificate it might be really hard to get.
Before you get married, there are certain things that you should discuss. Here are some questions that although they are aimed at military couples, they still pertain to many couples. There are also many books with questions you should discuss before you get married.