Don't try to chop down a difficult design problem with one swoop of your mental ax. Instead, chip the problem apart using ideation questions.
In their simplest form, ideation questions are restatements of issues that form the basis of a systemic problem. As an example, it would be difficult to attack the following challenge provided by a client: "We want you to improve the health care system." The problem, as it is currently stated, is much too wicked to approach with a measure of intelligence.
So, you'd start to try and approach that stated problem by breaking it down into questions. First, we'd restate the problem as, "What should we do to improve the heatlh care system?" Answering that question, from at least one angle, might be the broadly stated goal of your effort with your client. At this point, you can start to break that massive question down into a series of ideation questions that surface latent issues. How do people access health care services? Who provides those health care services? What people are not currently served by health care services? And so forth.
From here, the fun really begins. Select a key question out of those that you've written, then start to ideate around a key component of it as a tightly focused question. If we choose "How do people access health care services?" as our starting point, then we generate a series of questions that directly address the root cause of issues within it. "How can signing up for health care become easier?" "How can we more quickly admit people to emergency services?"
You can see how these focused questions speak to the initial challenge posed by the client, but have tangible outcomes. You could spend hours writing and answering questions when using this process, but the trick here is to be very selective in ideating against the questions that are most specific and most intriguing to you. The resulting ideas that emerge from your brainstorm will be more actionable as a result.
This approach may sound like common sense, but there is always a point in the design process where we begin to build our design execution off a set of baseline assumptions. Using ideation questions will force you to face assumptions buried in big, messy problems that we'd like to try and solve, but don't quite know where to begin.
And you can already see where this is helpful when you're working to frame the desired outcome of a client project, before you even begin...