The best ways I've seen to promote affiliates is to make them contextually relevant. Instead of treating the affiliate like an ad, mention an affiliate's product or service when it makes sense within the context of your content.
For example, I share my affiliate code (“noodle”) for Libsyn, Blubrry, and Spreaker when I mention any of those companies within the context of talking about where to get media hosting. I don't take a “commercial break” from a random topic and then do an ad for my affiliate.
When an affiliate is contextually relevant, listeners and readers are far more likely to take action on it.
Also ensure you're following your local laws and disclosing the relationship.
And if I may offer an example of what *not* to do (based on my own mistake)…
There are many… MANY opportunities for affiliate accounts. On my podcast, I joined Amazon’s affiliate program (find a podcast that hasn’t!). But, I thought, since everyone and their dog has an Amazon affiliate account, I should sign up for a few others – you know, to give my listeners a choice.
What hadn’t occurred to me is that I effectively nullified the monitization of my podcast and website because my listeners did, in fact, split their purchases through my different affiliate programs. Since every program has a base dollar amount in sales that you need to achieve before they pay out, it took a lot longer to see any revenue. In fact, I still have a few dollars “stuck” in affiliate programs because I didn’t reach that sale amount. And, since we shut down the podcast last year, those dollars are going to be stuck for a while.
It was a nice idea to offer so much choice but that decision negatively affected the revenue stream. But, it’s certainly possible to have several programs in effect if people take your excellent advice and mention specific products or services in the context of your show.
Most affiliate programs let you track with separate IDs or campaigns, which are great for using the same program with multiple shows.
But when it comes to similar programs, such as B&H vs. Adorama, I mostly pick one to be my primary, unless there’s a sale at the other.