I noticed that you posted an attractive new red and yellow banner for the Sands, so I put it in rotation yesterday. While it’s only seen about 2500 impressions so far, I’m getting only about half the CTR as with another banner of yours which has always been the best performer for me. I’ll keep running it for a bit, until I’m certain the lower CTR is for real.
This has to be frustrating for you guys. I know I’ve tried a lot of your different banners over the last couple of years, and we’ve just never been able to find a real performer.
My advice to you is to make LOTS of new creative, maybe a dozen different ideas. Hopefully, you’ll find one or two that get you more visitors. The investment will be repaid quickly if you’re successful. I think I’ll forward you some information about other competitive CTRs I’m currently seeing.
On a more general note, is everyone as bad at predicting the effectiveness of banners as me? 
The banners I like the best are usually terrible performers. I’ve finally learned to let the numbers do the talking.