If you're taking the "bid high intially" route, then you have to be patient. When your campaign starts, google doesn't have any ctr information on you specifically. However they do have their own historical numbers for the keyword you're bidding on and will give you the benefit of the doubt for the first 24 to 48 hours. (They'll give you a chance to prove you can get and maintain a high ctr.) Click through rate is one of the most important factors in getting low bids. Quality score was invented to make the cost per click formula have a mystery factor that only google knows. This way they can charge you $5 or $10 minimum bids, (ie you got slapped) and say it's due to low quality score. When in reality they're saying, "your campaign sucks, go away". Anyhow, back to when to lower the bids, the generally accepted rule is after 3 months they will have enough data to lower it for you automatically. I've been in niches where this happens after 1 week though. It depends on the volume of traffic and how high you can get your ctr.
From Perry Marshal's book, I learned that the more relevant your keyword and your landing page is, the lower you can bid on your keywords. 5$ per click is seriously expensive. If you try Perry Marshal's trick you can lower your bid to pennies and still get the best spot.
perry marshal is out dated and doesn't provide good bidding strategies. If you attempt his methods you will have a hard time on google. His methods worked about 5 years ago, when google was newer, but they have patched many of the tricks in his book now.