I also think this needs to be largely mentor driven. Personally, I dislike the cosmetic approach of putting up "You go girl" posters or the like. I understand it can help initiate a change, but I'm more in favor of just making changes head on.
I will admit that we have it easy on the Tigerbytes. We draw our team from a very diverse student population that looks like a United Nations group photo. All of our kids will spend some portion of just about every day as part of a minority in one activity or another, we don't have any one dominant group and the students are are used to that.
So, to answer the questions:
What have you done to be more inclusive?
What 1775 has done to be more inclusive is to make inclusion a core value of the team. We talk about it, we compare ourselves to other teams, we address any issues that come up rather than letting them slide.
What worked and what didn't work?
The only thing I can think of that we've done that hasn't helped was in our early years we thought inclusion would just happen. It didn't. It wasn't until we addressed it as a team and made it a topic of conversation that it became habit.
How do you address problems on your team?
If it isn't blatant, I like the approach Katie mentioned above. As a mentor, I try to redirect a conversation that's going the wrong way. I think the kids pick up where I'm going pretty quickly. In blatant cases, I will address it with the student (or mentor if needed) directly. Since inclusion is a core team value, it's fair game for a discussion.
I think the biggest mistake to make is to think that this topic will take care of itself. It won't. If you want an inclusive team, inclusive behaviors need to be modeled and reinforced. If you aren't where you want to be, have a team conversation and make a it clear about where you want to go.
Ivan