Philosophy in Three Points:
#1 Define the Problem
A solid design solution must solve for a well-defined problem. Clearly establishing the problem at the onset is a crucial part of guaranteeing a successful solution at the end. It's tempting to start developing specific solutions early on — but just wait! Every problem has a million potential solutions. They're almost all wrong. The solution imagined at the beginning is rarely the best solution at the end. More often than not, the initial problem isn't even the problem. Really poke at what makes that problem a problem.
#2 Map out the Process
Process is essential. Any decent designer can make a cool looking logo, rad website, or awesome poster. BUT — just because a design looks good, doesn't mean it is good. A clear process will assure the resulting design solution is spot on. Begin with the well-defined problem mentioned earlier. Couple that with an understanding of the project's constraints. Strategically look at how different directions can be explored. Refine these directions in a series of collaborative reviews to get to the best design solution.
#3 Design the Solution
There is a way to treat text so it's legible and buttons so they're actionable. Best practices are informed by what's been proven to work and are an important part of developing effective solutions. At the same time, design is hardly an exact science. A large part of what makes great design resonate is hard to quantify. Intuition is a real thing that takes a long time to develop. And feeling current without feeling derivative is important. On top of that, a designer must know how to interpret the client's needs (and whims) to develop a great solution. Sticking that landing is no small feat. If the above steps are in place, success is guaranteed.