Best way tp promote an affiliate product if you don't have relevant content already?

Personally, I'd always create my little site around the niche, never around an individual product. I do that even if I'm promoting one product only (which I usually am, right at the start).

One of the joys of affiliate marketing is that (unlike vendors) we have huge flexibility and we get to build up a real, asset-based business without being dependent on the continuity, reliability and availability of any individual product at all.

This is also true, of course, exactly as you say. But it isn't my main reason, to be honest.

I want my site to brand myself (or my pen-name) not someone else's product.

I'm an affiliate, so the primary thing that makes sales for me is the trust and respect that my subscribers have in me (even if it's "in me" under a pen-name, which it always is, actually). Not in a product.

That's what drives my income. I need to brand myself and build my list. That's what all my affiliate sites are there for. There isn't much income without doing that. Without collecting their email addresses, you can't keep them returning to the sales page, and not many people buy the first time they see it. Otherwise you lose nearly all the traffic you've worked to attract, and it's like trying to fill the bathtub without first putting the plug in place.

Creating a site around the topic is much better.

Even if the first product does not sell too well you build yourself some assets and you can then expand and maybe promote other products in that niche.

HP

There are a couple potential problems with creating a site specifically for one product.

First of all, if that affiliate offer gets taken down, your whole site is kinda screwed. Sure, you could pivot to a related offer, but that defeats the purpose of creating the site for one offer.

Also, if you give off the vibe that your site's sole purpose is to sell this one product it may come off as less trustworthy.

I'm sure it's possible to successfully create the site around the product, but it's something I would be hesitant to do unless it is a very lucrative and secure product.

Maybe I am the wrong person to answer here because I really hate building sites
But here it goes:
I use small properties that are free for my building, I use my bonuses for pushing the buy. This way it is very easy to just move on if the offers die and I can push a lot of offers very fast.

I would go for the general topic..this way you can expand if you find other new, interesting products to promote in the future.