As you find More of What’s Working, and do more of it, you should also find plenty of What’s Not Working.
If it isn’t working – Stop.
Yes, persistence is a virtue, and hard work is normally required to be successful.
However, unless you are inventing something or creating a new concept, you should have a pretty good idea that something isn’t going to get better if only you add more money or more time or more effort. If there isn’t any progress, it probably isn’t working.
If you keep on doing something that doesn’t work, it still won’t work. Stop doing it.
Quit while you’re ahead and Do More of What’s Working, and Less of What’s Not.