Last year I had 5 lenses in the top tier all year and for a couple of months it went up to 6 when a couple of my seasonal lenses rose to the occasion (at two different times). This year I have attempted to do very quick updates to each lens in my top two tiers every week ...........I have done this well for the most part, but there was a break when I was away. This has kept my tier 2 lenses safe and increasing, but my tier one lenses would increase for a day or two and then drop just outside(!)
There was one of my lenses that has flirted with tier one on occasion, but seemed to settle into tier two and I wanted to change that - updating wouldn't work so what would? The lens in question is How To Earn Money On Squidoo - it's a help lens that doesn't make any sales so in order to make me money I really wanted to get it into the top tier and keep it there. I finally seem to have cracked it and it has stayed in the top tier for a few weeks now and will hopefully hold steady.
I was never going to get thousands of visits a week on a lens that was solely for the Squidoo community so I had to make the visits count and to do that I decided to add some interactivity on the lens - it worked.
I've added 3 polls to the lens - polls are easy for people to click on and 3 polls for the length of the lens didn't seem obsessive. People are taking these polls and I think that's what is responsible for the extra push needed to get it into tier one and keep it there.
Do you have something to encourage people to interact on your lenses? Polls, quizzes, even guestbook modules are great ideas. On my Julia Child's Cookbooks lens - I have used several guestbooks to encourage people to leave their own reviews on the page. All three of these ideas are great ones to add to your lenses.
Take a look and see if you can add something to keep your reader on your page for a little longer.......you may find that your lensrank will improve as well :D
The other thing to think about is that the 'stickability' of a website (how long someone stays on your site) is said by many experts to increase your chances of making sales so even if your lensrank doesn't increase your sales might. I have to say that my Julia Child's lens has made a lot of sales so that seems to back up what the 'experts' have stated.