When I first started studying Japanese, I found a book called Essential Japanese Verbs by Setsu Migita and Y. Yoshimura to be extremely helpful. The book features more than 1,000 Japanese verbs and shows the various conjugations of each. Plus, a lot of the entries contain sample sentences in both English and Japanese so you can figure out exactly how to use the verb when writing or speaking.
The only drawback to the book is that it only shows the kanji for the featured verb on the page. Thus, the book isn’t particularly helpful if you’re looking to improve your Japanese reading abilities.
Overall, though, this is an excellent tool for beginner and intermediate language students. The only thing is, I bought it in Japan and don’t know if it’s available in the States. If you can find it, I suggest snapping it up quickly!