There's great information here in the forums. Here are a couple of threads that will help you (especially if you don't have the Official Game Guide).
Helpful link #1 and Very helpful info on this entire page (especially Arthur's tip).

I'm not too proud to admit that the first time I played VV5 I was completely frustrated as well. and after 1-1/2 hours I needed a break and to figure out a strategy. I figured it out though!!! Hang in there and keep trying! You CAN do this!