10% is supposed to be a very good ctr though there are people who get 30% ctr. It all depends on your keywords. If your visitor came to you looking for cheap hosting and he finds ads of expensive servers, he wont click.
You are already getting good CTR.Don't do any thing wrong to increase CTR,it might trouble with your Adsense account.
Try to experiment with the placement of your ads and if possible use an even more optimized template.
Structure your site well so the most relevant ads show in line with what the page is about. Good SEO Structure.
8.7% is good, ppl get 0.3%. you shud be happy with your 8 . color placment of ads can effent your CTR
Your CTR is already good. Anyway, Try different ad units like, 336*280 or 250*250 etc, and put them in different ad placements. Try different combinations of ad units and ad placements to see which one gives you the best CTR.