Since February Inside Adwords has been running a series of articles by Stephanie Lim about Adwords Optimization, here are links to the full set.

AdWords Optimization Tips: Part 1 – Assessing Your Industry and Audience
Helping you to understand your competition and Customer base.

AdWords Optimization Tips: Part 2 – Assessing Your Website and Goals
Evaluate your website and define your goals.

AdWords Optimization Tips: Part 3 – Account Structure
Use the information gleaned from Part 1 and Part 2 to structure your Adwords account.

AdWords Optimization Tips: Part 4 – Keyword Basics
General keyword advice and formatting, core keywords, and keyword variations and modifiers.

AdWords Optimization Tips: Part 5 – Beyond Keyword Basics
Refine your keyword lists to increase efficiency and conversions.

AdWords Optimization Tips: Part 6 – Ad Text
A guide to improving the quality of your ad text.