Practice everything you learn. Use what you learned speaking in class and speaking by yourself. Try to find some topic in wich you can use the grammar learned. Also, a good idea is to search for extracurricular activities, like games or online practices that entertain you. Practice makes the master.
You can find practice on multiple topics here! http://www.perfect-english-grammar.com/grammar-exercises.html . And some funny games here: http://www.eslgamesplus.com/intermediate-classroom-games/