It really depends on the amount of traffic you're getting and how much you're earning per click. Also it depends on the average time spent on your website per visitor. There are way too many factors involved that make this answer short and simple. Are visitors taking a look at your website and leaving within a couple minutes or even seconds? Then you should probably aim to put ads higher up and at the beginning of your content. If you're a start up site with incredibly high CTR/Google is probably going to look into your site and where your clicks are coming from. You can't just give a flat out answer as to what is a good CTR, you have to know how long your average visitor is staying and how much traffic you're getting and how much clicks are worth on average on your website before you can get a number for an answer.
Thank you for your answer. I don't know what is a high CTR. I am going through the learning phase. Yes, I have launched my site very recently. Here are some stats: I get around 100 page views daily (on average) All time CTR: 0.44% All time CPM: $1.44 What do you say ?