What's the most effective way you've found to keep your marketing team motivated and engaged?

Marketing efforts can be difficult to measure and attribute the effectiveness of. This means that when you are considered "Good" at your job in a marketing department, it's difficult to define and you often get stuck in a niche as there's a reluctance to find someone else to replace you. That's how I found it when I was doing communications and copywriting. Having a clear career progression path gives you something tangible in a department that has a variable and conceptual nature.