The best study plan for re-learning?

[Tricon7]

I studied Spanish in college and could make basic conversation at one point. But that was 20 years ago, and I've forgotten most everything beyond the basics. I'm familiar with everything in the language, but my grasp of the verb tenses is terrible and my vocabulary is seriously lacking. My grammar is better, but it needs work, too, so I'm trying to figure out the best method to pick up the studying again if anyone has any suggestions.