If you take hits and you get a burnt taste or a harsh vape, its too much.
When I first started building on an RBA and RDA I had that problem. I was getting totally shitty flavor, the vapor was harsh on my throat and tasted a little burned. Couldnt figure out what it was at first and just thought building wasnt for me. Until I just tried it one more time one day after watching a video online about wicking properly, and voila, perfect.
The way I wick is I use enough cotton so that it slides through the coil with just a little resistance. You should be able to slide the cotton back and forth fairly easily but with some resistance. The way I do it is after I slide it all the way through the coil I just tug it back out a little bit, and if it forms a little hump/knot on the opposite side, its the right amount. If its not enough cotton it wont form a hump, if its too much the hump will form and the cotton will start pullling apart.