Do you know the urge to start from scratch, once you almost finished solving your problem? That's because by then your understanding of the problem has evolved.
Coming up with ideas to a problem does not only give you solutions. It requires a certain degree of immersion, which will always evolve your understanding of the problem. However, this process can be messy. It is easy to lose sight, start to focus on the wrong problem, get bogged down in unimportant details, and jump too fast to solutions rather than understanding the problem. People tend to think creativity comes from the removal of all restrictions. In reality, it requires a thorough process that requires different mindsets and the discipline to follow. Approaching each step with a distinct mentality is crucial.
Here is how I approach a new project or the ideation for a single concept. It is a simple 5 step approach, but each step comes with a distinct mindset. I look at it like jumping from a diving tower for the first time. The moment when you jump represents the ideation moment, but there are a couple of crucial moments before and after.
Time to jump and explore. Focus only on the ideation. Write, sketch, draw, whatever makes your thoughts tangible. Let your ideas flow. As when you jump, there is nothing else that matters now. It should be just enough to get your ideas across. Focus on the aspects that differentiate your concept. You can keep common parts vague to save time. Look at your problems from various angles and provide different answers. Go for quantity and create at least 20 different concepts. Try to keep an open mind and don't judge. This stage is about quantity, not quality.
This stage will test your understanding. You will run into new questions, most likely about details and dependencies. Once you are finished go back and find answers for your questions, either internal or external.