You can launch a bigger product without having a relevant following, but it's exponentially easier to do if you've already shown a track record of producing things and helped people to the point that they're interested in what you create.
I can't advise enough to start with an info product, digital good, or blog in a related industry to what you want to create in order to build an audience. If you're not sure what you want to do yet, just start writing and sharing knowledge. Create free resources to help people, but do something. And hopefully at some point, those projects are even contributing a little extra cashflow to fund the bigger plans.
Ideally, you can start well in advance of your plans to create your bigger product, but even if you can't, planning even a year in advance can really help. If you're passionate about a topic and create a combination of smaller free resources that save people time and have that lead up to larger paid products. Then, ideally, you're building an email list the whole time. This is the key part. People need a way to follow the future work.
The other key is to make sure that all the writing, free and paid products should focus on solving someone's pain. If you create everything with a focus on helping people and giving them great value, it will all come back.
There's a lot of products that started this way and had some benefit from the initial products. Again, it doesn't have to be done this way, but it helps.
- Product hunt started as a simple email newsletter. As it gained a larger following, it became clear that it could be bigger, and it was easy for them to take the next step.
- Freckle was started by a couple that had been blogging and contributing to popular open source libraries. It wasn't everything to the launch, but it helped.
- I launched my own app after about 8 years of blogging and speaking at conferences. I gave away free resources here and there and built a very modest following. Then I started blogging about ideas with no plans of building an application. But that modest following turned into a lot of people who we were really interested and encouraging in what I was doing.
Even though having a following helps you get it off the ground, that's all it will do. It's like a jumpstart, but it's unlikely to skyrocket to enough revenue to cover your salary. Chances are it's still going to be a 2-4 year cycle to grow the business, and that's where many give up.
There's really countless ways to start, but starting with small products and letting those snowball into bigger and bigger products is definitely one of the proven ways to make it a little easier on yourself.