Studying the bible is a very important thing to know how to do properly. If done wrong, you could end up believing something that isn't true, not believing in something at all or just not understanding something God wants you to know.
The very first thing you should do is pray. Pray that God will guide you to what you should study and for wisdom. Prayer is essential for bible study because you are communicating with the author of the most important book in the world and to have the gift of understanding it is the most privileged thing ever and to not understand would be very unfortunate.
If you are studying a Epistle you should know who the audience is. Not knowing who the letter is written to can actually make it difficult to determine what the verses mean. Often one word can have several different meaning and it is very important to know which one it means for every verse. For example; Romans 8:32 ‘He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us everything?’ If you just read this verse alone you could say “us all” means all man kind but the book of Romans was written to “All who are in Rome, Loved by God,called as saints” which means Christians and in the next verse it says: “Who shall bring any charge against God’s elect? It is God who justifies.” So clearly Romans 8:32 is talking about Gods elect, the people who are called by God not every one in the world.
There are other things you should add to your bible study,such as commentaries and a lexicon, a book that tells you the actual meaning of the original Greek or Hebrew it was written in.
Finally, after your bible study, you might want to talk about it with some body in order to remember it better.