Hey pal,
Firstly you need to add any possible negative keyword in your campaign-adgroup negative keywords.Then make your ads as more relative with your keywords.
Ride the link and download a free google adwords report that will answer any question you have regarding adwords:

Adwords Made Easy

All the best

CTR, there are lots of info and ways.

but basically the logic is this.

in priority.
-attractive ads.
-correct placements.

if your ads is attractive, eye catching, makes people want to find out and click on it then CTR will go up.

placement, this is 2nd for a reason. its important but 2nd to attractive ads. you can have an ad on a search or site that has no relevance but it interest people and CTR increase, but it only works in some cases.

so be safe and take into consideration this 2 factors.

and you should be fine.

Thanks for Information. Its very Nice and Helpful Information About "CTR in Google Ad Words".
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