My tip: Have one main credit card. Have a second one that you use for necessities – such as groceries or gas – that offers rewards for those purchases (a lot of cards do) and set the second one on auto-pay. You should be able to pay off a smaller amount on auto-pay if it is a necessity. If you think you cannot, then you may need to cut down a lot on expenses.
Good comment Jason, at some time in the future Amazon may decide they have so much market share they don't need affiliates anyway. I mean, if you're just sending them people who are already Amazon customers there's not so much benefit there for them. Or they may decide to only work with select HIGH QUALITY affiliates and the average "affiliate site" owner will not be chosen.
Provide excellent customer service. Answer any questions buyers post as quickly as possible. Be professional and courteous. Positive communication builds your reputation with buyers and gets you return business. Also, package your product well and ship it out quickly. Allowing an item to become damaged or taking too long to ship can negatively affect your reputation among buyers. Wrap all items, especially fragile ones, in appropriate packaging. Commit to shipping items as soon as you receive payment.
I have a free WordPress website with 1000-2000 visitors/month. I was trying to place Amazon Affiliate ad links last night and failed/flailed mightily. I would paste the links into my posts in the HTML mode, switch to Visual mode, and could see the image. However, every time I tried to save or update the post, the image reverted to the gangly hyperlink. As some suggested, I tried cleaning the links of any formatting from the copy and paste with text edit. No dice.