Continually adding your own pages will only get your Stumble account frozen. The site is for promotion, yes, but not just your own items.
The best way to continually be in the rotation is to have others stumble your items. There are stumble teams that you can join that will assist with this.
Also, in my experience, Stumble can be a hit or miss on any given day. It all depends on the who/what/when/where searches by people on Stumble. In the past, photography and crafts would bring high views. Then, bizarre/oddities would get the high views.
Tagging is important, though I do not believe that using a large number of tags will help as I don't think it recognizes tags after a certain number. What that number is I do not know. I have hear rumors of 5 but I could be wrong.
Almost a year ago, the very first time I was stumbled, I received thousands of views on the photo that was stumbled. However, a cautionary tale here. That item now has over 10,000 views and it has never sold.