Write, write, write. The best way to remember new vocabulary is to use it, and the best way to start using it is to write with it. You can also speak, but that requires more practice, because speaking has to be faster.
I always get my students to write. That tends to be the objective of each lesson. If you know how to use something in writing, you've successfully learned it.
It's also the method I use when learning a language myself. I'm learning Spanish right now, and I try to get some writing done each day, even if it's just a few sentences.
Writing also has the benefit of giving you the ability to get corrections from others and therefore seeing the words used properly in context. Seeing the words in context is entirely different from learning a bunch of random words. It's a lot more useful. Plus, context helps you remember words better.