I have always held that while grammar is an integral part of learning any language, studying grammar as we used to back in school isn't going to help much. If it did, you wouldn't be asking this question.
Grammar has to be learnt in context, much like vocabulary and it is absolutely not worth your time to memorise complex grammar terms and rules or even be aware of them in most cases. As long as your basics are clear and your foundation is strong, you are set. So, stop fretting over the names of tenses and the forms of verb and the rest of the blah, unless of course, you intend to become an English teacher, like me. If your goal, however, is to speak fluently and impressively, you don't need to learn grammar. You just need to use it correctly. And any English language teacher, worth her salt will tell you so.