I've had to do something like this for an established company I work for to grow subscribers, as well as a startup I'm a part of.

It will be hard to give you any specific advice without knowing your exact business model and services.

But I would start with your own data and your current customers. Why did they buy from you? How did they hear about you? What do they like about the product and what can you improve?

Analyze your sales funnel and website metrics. Do you have a lot of leads but low conversion or vice versa? Once you answer that drill down to get a solution.

Where are your leads or highest converting customers coming from? Can you double down or exploit anything there?

Then start a list of areas to test with specific hypothesis and a process to test, analyze and iterate.