What size tank do you have?
I have a 20L tank and my humidity stays pretty stable.
This is my set-up:
http://ball-pythons.net/forums/showt...ss+Tank+Set-up
Check out Step #8 in that pictorial. So, that specific water bowl gives me the humidity I need - moving it closer or farther from the heat pad.
Also, I use cypress in winter and aspen in spring - that is, I use cypress when the room humidity is low and then aspen when the room humidity is higher.
With the foil top, the cork bark surrounding the tank, substrate and choice of water bowl, it's enough for me to raise/lower humidity by 20%.
I usually don't need to spray (sometimes, I spray the cypress substrate a tad bit when in shed) and I don't use wet towel.
I put clumps of wet sphaghnum moss around the hot-side hide (not inside) if I'm using the heat lamps.
That's really all I do.
P.S. Make sure you read the posts in the entire thread before following anything on that set-up thread. There's some stuff that is not good on that set-up - like the tape, the positioning of the acurite, etc.