Can anyone give me advice on how to study better for college?

I am starting my 2nd year at a community college this fall. I did not study the best last year, but my GPA is still a 3.4 and I don't want it to go back to a 2.0. I want to try to keep my grades to As and Bs this year and I need to learn to study harder. I am taking a history and gov. on the same days. On the other days I'm taking English Comp. and Math. English is my easiest subject, but I struggle in history. Can anyone give me advice on how to study well so I can pass my tests? Last year I failed most tests in history, because I think I was studying the wrong way and ended up dropping the class