Only because a product is an affiliate product does not matter if you can't be creative about promoting it. You do not need to use their marketing materials to promote it.
To make this even more useful to your audience, you can add your own freebies, checklists, updates and more to the product. Consider some creative and effective ways of promoting affiliate products.
1. Create a How-To Tutorial Upgrade
If you create a tutorial for the product and offer the tutorial to anyone who buys the product from your link, you can incentivize them to buy it. The tutorial will help people who are on the fence but worried they may not be able to use the product. Alternatively, you can give the tutorial away free before purchase as a lead magnet.
2. Write Interesting Reviews
Publishing reviews will always be a good way to get an affiliate product promoted. People could read what you get with the product and instead choose to purchase it through your affiliate link or not. The interesting part about reviews is that the more honest you are-even if you don't like the product-you will be making more sales.
3. Create a Round-Up of Products
If you understand about five to ten brands you're an affiliate of (or at least you're an affiliate of some of them) that they all do similar activities, create a post listing them all and discussing them all. This works fantastically in a chart that includes the cost and a product link.
4. Link to Products within Your Content
Even though your post was about something else, it's a great place to link directly to other reviews you've made or other information that helps promote that product, as long as you mention a product or subject in passing.
5. Host a Webinar
Webinars are excellent ways of promoting affiliate products. You don't need to be the product creator for basically selling it as if you own it.
6. Create a Resource Page
You should have a page on your site which is either "resources that I use" or "tools that I use" or something that works for your viewer. List all you use in the correct category, trying to link to affiliate links for such things which have them.
7. Create a Case Study
People seem to enjoy other people's stories. Creating a case study about someone who has been likely to succeed with that product is a great way to introduce your audience to that. They'll love to see others succeeding. This person need not be someone who has bought the product from you.
8. Get a Higher Discount
Ask the creator of a product to give you a discount code. While this will eat into your profit, it's not really going to make the big difference because the product is digital. It will however make the audience more interested in buying from you as you have the discount.