When beginning your affiliate marketing career, you’ll want to cultivate an audience that has very specific interests. This allows you to tailor your affiliate campaigns to that niche, increasing the likelihood that you’ll convert. By establishing yourself as an expert in one area instead of promoting a large array of products, you’ll be able to market to the people most likely to buy the product.
Next, you’ll want to pick a WordPress theme from somewhere like ThemeForest, Elegant Themes or OptimizePress. This is the barebones design of your site, which you can then customize with your own branding, copy, and images. That being said, you don’t want to cheap out. It costs less than $100 to buy a theme that will make your website look professional (and you can upgrade to a completely custom design once you get the business going).