Here’s a pretty good list of Top 10 Adwords Mistakes.
- creating a long list of less than targeted keywords
- failing to identify unique aspects of your product or service
- a lack of keywords in your ad text
- directing users solely to your home page
- creating single ad groups
- utilizing single campaigns
- using broad match only
- failing to optimize ad serving for your ads
- failing to track results
- entering the content network without modifying bids
Like all lists, take these rules with a grain of salt. For me, number nine is the most important. It doesn’t really matter how people approach Adwords, so long as the results are positive.
However, I think the most important factor has been left out – know who the audience is, and what they want. The marketing side of PPC is often down-played or omitted, but it is the make-or-break factor for search marketing campaigns. Without that knowledge, PPC campaigns can quickly become very expensive.
You can run profitable campaigns by knowing your market better than the other guy. Here’s the Wikipedia entry on market segmentation. The most important aspects as far as SEM is concerned are the readiness-to-buy stage (especially important for affiliate marketing) and sales effectiveness (i.e. focus resources on prospects most likely to buy your product).