Are you an expert in conversion optimisation, sales funnels, SEO, website building, copywriting and proofreading? If so, you have a better chance than most newcomers. Chances are, if you’ve only just heard about affiliate marketing, you don’t have all or even any of these skills just yet. In this case, settle down for the long haul. This is going to take some time, but you will get there – as long as you don’t give up along the way!
One great way to get ideas for related products to promote is to look at the stats/reports that Amazon gives you to see which products readers are buying. After a while you’ll start to notice that they’re not only buying the products you directly promote but other products as well. Some will be completely irrelevant to your niche – but many times trends will emerge that could signal other products that it might be worth promoting.
In the past, large affiliates were the mainstay, as catch-all coupon and media sites gave traffic to hundreds or thousands of advertisers. This is not so much the case anymore. With consumers using long-tail keywords and searching for very specific products and services, influencers can leverage their hyper-focused niche for affiliate marketing success. Influencers may not send advertisers huge amounts of traffic, but the audience they do send is credible, targeted, and has higher conversion rates. 
Set reasonable expectations for earnings. You've only invested $20. You're going to make 5 percent on most products. That means that you need to sell $400 worth of stuff to make back your investment. You get credit for purchases customers make while at Amazon besides just the product you linked to, so it's not as hard as it may sound. It won't make you rich, but it's not hard to be profitable, and the income builds over time.

Videos also make it easier to build a relationship with your audience; you can talk right to them, and they can hear your voice (and see your face, though that’s not always necessary). Plus, not only are you sharing what the product looks like and how it works, since you’re the one who’s showing your audience how it works, you’re also building your authority with them as an expert they can trust.
It seems nowadays many bloggers are obsessed with this monetization stream, clamouring to find out how they, too, can make money off blogging through affiliate sales. This popularity has led to one very negative consequence: information overload, and not enough answers. After a few email exchanges, I realized some newbies were petrified of asking basic questions… in fear of sounding dumb.

Indicate who is the main contact for the account. Select the first bubble, labeled “the payee listed above,” to indicate that you are setting the account up for yourself. Select the second bubble, labeled “someone else…,” if you are setting the account up as a representative of a company. Click “next: your website profile” to finish setting up your Associates account.[4]
Affiliates are most successful when the products they promote match the interests of their followers and subscribers. In addition, many successful affiliate marketers advise recommending and promoting only products that the affiliate is personally familiar with. That’s because familiarity with the product, program, or service helps build trust between the affiliate and end-user.