What's your method of remembering vocab?

I am sure many of us learners have that never ending problem of forgetting vocab from previous lessons we learnt. It seems like I often am just replacing the words I learnt in previous lessons with those I am learning in the newer ones. How do you guys keep the vocab you learnt from previous lessons in your head? Weekly review? Weekly listening to each podcast you learnt? Hearing anyones study style would be interesting...