Hi
I tried this to improve my french vocabulary (french is not my mother language) and for activation I just tried talking more in French and also watching french TV (since I live in France). Forget about previewing. I can assure you that I saw results in 3 weeks.
If you want to improve your mother tongue vocabulary then some people recommend to write (an essay for example) and then try to re-write it in a different way using new words.
For more information trying doing a search on the forum.
Good luck!
[This message has been edited by Yiorgos (edited October 15, 2001).]