There’s Adler’s practical grammar, for instance, which has greatly worked for me.
I used Benjamin D’Ooge’s “Latin for Beginners,” and that worked for me. It covers all of Latin grammar. I would also read through both Lingua Latina books. These books are simply the best resource available for practicing improving your Latin.
What resources are you using at school? How do you learn best?
I second the Lingua Latina suggestion, as I always do- I’d also suggest picking up the College Companion book which explains the grammar in English for the first book.
I’ll second Lingua Latina in conjunction with the College Companion. When learning on my own I quickly ran into deep water with LL on it’s own. The Companion is geared to work directly with the text examples and covers both the grammar and the vocabulary.
There is also a Teacher’s Materials book available that has the answer key to the exercises in the text as well as copies of the exercises if you want to xerox them to work with them.
You will still want a full grammar and a good dictionary.
Depending on your English grammar skills you might consider English Grammar for Students of Latin by Norma Goldman. I’ve found it invaluable for succinctly explaining grammatical concepts and illustrating it in both Latin and English.
Go with Lingua Latina. The fastest and most effective way to learn Latin.