As a builder/developer, marketing often isn't considered "fun". But you need to do it, else the build was for your personal entertainment/learning exp (which is sometimes a good thing).

What I do is stop building and focus 100% on marketing - well, 90% because I can't help myself. Even if this isn't as "fun", you need to switch modes and stop building.

As for my approach, I start with Google Ads + SEO/AEO. Google ads can get results in a few weeks (Google does have a learning phase) and SEO and AEO is a much longer process, which can be months before you see results. I use AHREF to check my SEO/AEO progress. While AHREF isn't a direct measurement of Google, I've found their DR to be correlated with my organic traffic.