When people find your blog or optin page, they will leave their name and email address in exchange for your free giveaway. Usually this is in a form of a short report on your topic. This report can be several pages in length or longer if you choose.
The most important thing is to include your contact information on every page, as well as affiliate links within the report. These must be relevant links to products or services that make sense to your target market. As people get to know and trust you they will be even more likely to click on your links and make purchases.
People on my list email me regularly before they make a purchase. They discuss the product that I am promoting, and then ask me to make sure they are buying through my link. This is an honor for me, for I know that they trust me to help them make the best possible decision for them as individuals.