Turn off your content network:
If you want to save money from losing on content network then make it off because sometime you will get traffic from untargeted area there could be chances to click your ads out of curiosity

Always Use keyword tool:
By this tool you can create search phrases. I am giving you a list of some most useful & free keywords tool..
Lexfn
The Overture Keyword Suggestion Tool
Good Keywords
Nichebot

Don’t use bunch of unmatched keywords into one group:
Means you if you are selling health products don’t use “health related product” & “make money using health product” in one group. – divide this into own separate category using common keywords.

If you want to lower your CPC (cost-per-click) rate always use your own keywords from headline, title but include common keyword into one group.

5. Set affordable budget per click:
For getting maximum cost-per-click rate divide your commission by 100. Means, assume your commission is $20, after dividing this you will get maximum per click rate 20 cents. That defines if ONE person out of 100 clicks your ad you can get 20 cents/click.
If you want covert this ONE into 50 then you can take risk by raising your bid amount little. But there is no guarantee. So, if you are beginner on adwords Be limited for setting budget.
If keywords that you are willing are costly than your maximum CPC then try to use related phrases that could charge the same ad.