Client-led product work
One of the most effective things that has worked for growing my small business is client-led product work. What I mean by this is that I have a set of small SaaS products that I sell, but I get approached by people who want different features or off-shoots of my products. So, in exchange for a bit of money up front, I develop what they want and then roll it into my existing product offering.
The great part about this is that the new feature is already validated to some extent: at least one person is willing to hand over money to make it happen. That being said, I do go ahead with some product features even without money in hand, if I think that the opportunity is big enough to justify or the client has strong enough buying intent. The key though, is to make sure that the product extensions are actually in line with the strategy that you have for your business.
If you build something that is not in-line with the rest of your products, your brand, and your marketing, there's a significant risk that this will become one-off work, similar to freelance. Even that can be ok though, under the right circumstances. And really if that is the biggest risk, structuring your product-work this way doesn't have big a downside.
The issue I'm finding though, is that even if I build a few extensions and features that are tightly grouped around my core product vision, it is still difficult to bring everything together into a coherent product with clear marketing and documentation. That's a big priority that I have in the next few months. But first I have a few more client-led features to deliver.