Sometimes the best way to get unstuck and come up with a brilliant idea is to generate new ideas.
One straightforward exercise to do is to take a piece of paper and write a list of 100 things.
100 ideas for starting a business.
100 ideas to increase my income.
And so on. After that, group them by the relevance and start exploring the top 3. Then the next and so on.
Thomas Edison needed many tries to come up with a brilliant idea. This is what you must do as well, try, error and learn from it.