Well, I don't know how everyone else keeps their humidity up...but I use a hand held mister. The cages we use hold humidity really well and a misting once a week seems to do it. We've not graduated into anything fancy...but a mister from walmart seems to do it, the kind you see Moms spraying their children's faces with at soccer games. I know of people who use plant misters (handheld, something like a Windex bottle for botanicals). We also offer our Burms two water options, one bowl on the warm side of the cage, one on the cooler side (it seems to keep our humidity in the upper ranges when we have one on the warm side).
If you are lucky enough to have a cage that holds humidity well, I'd suggest starting out right after you've cleaned the cage with any suggestions you get on the forum. That way you're starting fresh and have a chance to watch the humidity with few variables for fluctuation.
Good luck!
Sam