I'm a fan of using different techniques for improving thinking. Here's a write-up on Six Thinking Hats. This book presents a simple and effective thinking framework. What I like about the approach is that it's both effective for individuals as well as a team. What I also like about the approach is that rather than focus on trying to change personalities, it creates a way for different personalities to play well together. Imagine the time you'll save in meetings!
Because Six Thinking Hats uses the hats as a metaphor, nobody gets a label. Instead, the entire team can put on the relevant hat for the task at hand: white, red, black, yellow, green, or blue. Imagine the surprises you get when the dominantly data-driven put on their green hats and get creative. Better yet, imagine what happens when the overly optimistic put on their black hats and play the "devil's advocate"?
What's interesting is this type of mode switching already happens. For example, in security we use white hats and black hats. On my team, I often ask, "what's your gut say" to tap into intuition and emotions. If I see the team too optimisitic, I ask "why won't this work?".
I think having a simple set of metaphorical hats and rules for the game will really help improve thinking and collaboration, and avoid the stale-mates that can often happen in meetings. As the author puts it, you "think your way forward versus judge your way forward."