Check out this cool "how-to" infographic I found from nobeefhere.com!
The only difference in how I make mine, is I just use tap water (if I'm using water as a base) because the water here is pretty good, and I don't have a filter anyway, and if I use any sort of sweet, it's almost always dates (because they're sweet, have a flavour, and are quite good for you), or occasionally raw honey.
Stevia I personally don't care for, I prefer raw honey to agave, coconut nectar and palm sugar are SUPER expensive here, and I can't have maple syrup in my home. Seriously, I have a PROBLEM. The problem being I LOOOVE IT and find way too many reasons to inhale it if it's in my pantry!!