If there is one simple, golden key tool to help a student learn a language it is probably flashcards. I took three years of French in high school, we had a weekly vocab quiz of twenty to thirty words every Friday, and moved on to new words. I probably had quizzes on over a thousand words by the time I finished with Français my junior year. I will tell you what, I remember almost no words off the top of my head almost two years later. So instead of repeating the French language I decided my first week here I would take the language of the Church; Latin. By far the most fulfilling and engaging class I have ever taken. It has improved my understanding of grammar in the English language, which was terrible in high school, and I actually know what is going on everyday in class. Other than the excellent teaching of Professor Hartnett, I would say the large stack of probably 400-500 words on my desk at the moment to be key in any success I have had in the class. In French my issue was always not understanding the words as well as the grammar. Well, big surprise, when you know the words the grammar of a language tends to become a lot easier!
So study, review, and make flashcards prospective students. It makes life 100x easier when you are here.