What would you consider a low CTR? 1% is probably about average. 4 or 5 is very high. Have you tried putting up a custom Google search? For some reason, I have always managed around a 10% CTR with every one I have ever used. They work a treat, if you restrict the search just to your domain then even if a few things show up, Google will throw up four relevant text ads which will either catch their attention first, or may even fool them a little, not sure. You are obviously gonna get a higher CTR if your writing about specific products. Let's say you are blogging about Michael Jackson touring the UK, then the CTR will be good if advertisers throw up "Get your tickets here" kinda ads. You should also test your ad placement, think about putting one blended ad at the very of the page so it is the first thing that your visitors view on your site.
Most people average at around 3%. You can have it at 5% easy if you do some tweaking. For many years I had mine at 5% ~ 7% but now it has dropped to around 3.5%. People have become quite accustomed to Adsense ads, so CTR is bound to fall even more over the years.
Don't worry man, My CTR is some time less than 1% means it some time goes on 0.xx% and some time it becomes normal between 3 and 4%... so just have good traffic.. and it is also depending on your site design/template
I forgot to mention the ad channels. Use channels to see which ads are working well and which aren't. This feature really helped me in determining the best and most lucrative ad placements.