[How do I make Realistic Water?]

I have made and almost completed a map. The last thing I need to implement is the water. I can't seem to get the lake, river or waterfall to look or act correctly. Does anyone know where I can find a good Tutorial covering water, or if it doesn't exist is someone up to the task? Or even better, can someone just give me a quick list of steps. Nothing fancy... somthing like:

1) Select water object

2) Clck Map editor

3) Choose .....

4)

Thanks,

Lowjack.