* Start small, just like the author did. Try to spend as little as possible, either the 1p/click minimum or target the bottom of the page (position 9.9 so you're just "above the fold"). Cap your spend.
* Measure, measure, measure. It's not even worth starting a campaign unless your whole site is being measured in every way possible. Personally I'd recommend tailing the Apache logfiles in real time to start with, rather than relying on an analytics package. You can move to analytics later once you've got the deep understanding from the logfiles. Also, save those logfiles forever.
* Don't rely on Google's tools for choosing keywords etc. They seem designed to waste your money (no surprise there!). Instead, look at the natural and paid search terms people actually use -- by following those logfiles -- and generate your keywords and your negative keywords from there. Be careful with broad-match keywords. We tended to use exact match only.
* Don't use consultants, positioning tools etc. At least, not to start with. They're all expensive and won't be as good as doing it yourself. When you've got the deep understanding, then you can go with 3rd parties if you choose.