1) Open link using _blank target
This will make sure that visitor open a new window tab so that the visitor will not leave your website easily.
2) Background? Refer to 101 Quick Tips Pg 8
Background should be light in color, no fancy backgrounds
3) Get sitelinks on your website, however, for now only authority sites get sitelinks
4) Find keywords using Spyfu, Google Contextual Tool
5) Text ads (CTR Higher)
6) Niches may affect CTR
Buyer niche get decent CTR
Freebies seekers only want freebies and will not increase your CTR
Women niche get higher CTR
7) Look at your competitors websites to see what ads appear in their website
8) Some niches to go for
Remedies for health improvement
Fanatic hobbyists
Job seekers
Reviews (eg. Air Con pa 64466)
Eg. How to Buy, how to choose..
9) If 1 keyword in the niche has high CTR, then other kws in the niche will have high CTR too because same target advertisers will target those kws as well.
10) Put images below the fold as images attract attention of the eye movement
11) Split test with at least 500 unique visitors
12) Write Good content, especially on the first few sentences
13) Space out more use 150-160 characters in meta description
14) Enable related articles on CTRTheme
15) Remove social sidebar, etc that will distract the visitors' attention
16) Remove Search Bar
17) Put basic links like about us, contact us, privacy policy on the footer