Find the weak spots, the vulnerabilities, and the imbalances and focus the majority of your energy there.
If you can find a weakness in the market or a need unfulfilled where you are strong, hit that spot hard and don’t worry about being “well-rounded”.
Being narrow and focusing on a niche will work wonders for your business or your project.
So get good at something (or figure what you’re good at doing) and find where you can fit into the marketplace and go deliver!