Not necessarily, but a blog is really the best promotional tool. With that said, you can always use methods such as PPC or advertising to promote a product. This is more like hit-and-run affiliate marketing, however. The best way to make the most out of your affiliate marketing opportunities is to have a blog and use it for hard and soft promotion.
Using a food delivery service can’t necessarily earn you money, but it can help you save you money if you constantly find yourself throwing out half the food you buy. Food delivery services send a box of food every week with new, sometimes unique vegetables, meat, fruit, and so on. If you don’t have time to shop and want simple meal-prep that leads to a good meal, a food subscription service may be perfect for you.
Find a profitable niche. Starting with your interests, write down as many niche ideas as you can. Think about topics people might search online. Ideas include passions (like surfing or body building), fears (like spiders or speaking in front of crowds) and problems (like getting out of debt). Do keyword research to see it others are interested in the topic. Find out if a domain name is available that matches the keyword 100 percent. 
Tradedoubler was founded in 1999 by two young Swedish entrepreneurs. They have offices in the UK and multiple countries throughout Europe, including Sweden, Germany, France, Poland and Spain. Their focus has always been to provide smarter results for both clients and affiliates through technology. In 18 years, they’ve amassed an army of 180,000 active publishers, connecting them to over 2,000 merchants in Europe and the UK. Many of these merchants are household names.
The topic you choose must have enough depth that you can create a lot of content for it. This is important for building an authoritative site, for search engine optimization, and most importantly, for the end user. If you don't have enough content about a topic, you're not going to be taken very seriously as an authority on the topic and it's unlikely you can convince someone to make a purchase from you.
Making Sense of Affiliate Marketing is a great learning tool, even if you are a brand new blogger. By taking this course, you will start off blogging the correct way. You can learn from my affiliate marketing mistakes and learn the best ways to start making an income by being an affiliate. Through taking this course you are sure to grow a profitable blog quicker than the average blogger, as you'll learn exactly what you need to know about affiliate marketing. So, even if you only have one blog post, you are ready to get started with this course!
I think content marketing is absolutely huge for affiliate’s, especially going into 2016, I think it will increasingly become something that will have to be adopted to gain domain trust, authority and good SERP rankings. Google loves quality content and if you want your website to stand the test of time, white-hat SEO is a must and content marketing is king!