A good walkthrough of the elements that make a landing page effective.
Juan Martitegui of MindValley Hispano wrote this excellent article for the 500 Startups Blog. He describes several simple and practical techniques to cut through the complexity of Adwords and zero in on getting the biggest bang for your Adwords dollars.
A simple, quick read from Hubspot that outlines some common alternative lead generation techniques to replace cold calling (which has horrible conversion in the first place). You may have considered at least some of these already, but the post is a good checklist.
The author describes a systematic process he used (and that you can replicate) to engage bloggers in order to generate leads for his startup.