Ways to use less electricity...?

I'm a single mom living on a single income and I recently moved to an apartment where I have to pay electricity and water on my own. I have 2 hot water heaters, one for the bath and one for the kitchen/ washing machne. I'd like to know any ideas for saving electricity. I'd also like to know if preparing a meal in a crock pot before I go to work, is actually using less electrity than using the oven/stove when I get home from work?