Whereas, you are a beginner, So first build a website with a popular subject that you are interested on.
Don't take any black hat SEO method. Just build a good network with readers and other people through advising, writing valuable and interesting content. Mainly don't focusing on search engine just you add many content based on your readers' behaviors.
You know, Many webmasters believe that a Thin Affiliate website is going to take poor ranking. So avoid it and take useful and valuable content to get rank for a long term in SEO.
Finally see above everything I wrote about content, Yes this is the key of your affiliate program. So friend target your audience to give them original and valuable information through your best writing skill or professional writer . Don't rewrite or scrape others' content.
Best of luck.
