So by popular request, here is how I do it. Firstly I use Google Adwords keyword tool, the type in my keyword, this returns a lot of keywords and basically I take them all. Next, the primary keywords I want to target I shuffle them around almost back to front if u like for example:
Keyword: cheap dog kennel
twisted: dog kennel not cheap
In other words, playing with the keyword.
Having built up a BIG list of say 1500 Keywords all twisted I then make the campaign, when selecting the countries I choose USA and Canada ONLY! I then set the default amount per click to 0.09c per click and the same for content 0.09c per click. After the ads approved (I only use text ads, never images- EVER!) I wait for a few days checking each day to see any impressions.
If no impressions I raise both levels to 0.11c per click, once I get some impressions and 5 clicks I slowly lower it 1c per click per day to hit 0.01c after say a week then the clicks just keep comming

Best
Mike