In general, it's best to use as little water as possible, and cook until the vegetables are done to your satisfaction. It isn't necessary to thaw frozen vegetables first, but you might want to thaw greens a bit to separate leaves.
For most frozen vegetables, use 1/2 cup of water for every 2 cups of vegetables.
Use 1 cup of water for every 2 cups of lima beans.
Corn on the cob should be cooked with enough water to cover completely.
Vegetable size can significantly shorten or lengthen cooking times. Here are some basic times:
Spinach -- 3 to 4 minutes
Turnip greens -- 15 to 20 minutes
Other greens -- 10 to 12 minutes
Summer Squash or Zucchini -- 8 to 12 minutes
Large lima beans, cut snap beans, broccoli, carrots, cauliflower, corn and peas -- 3 to 10 minutes.
Page 1 - Vegetable Freezing Guide: Blanching and Packing
Page 2 - Preparation and Blanching Times for Specific Vegetables