If you wait till you near the end of a UX design project for a big creative review-style / reveal meeting, you're doing it wrong. Collaboration is the name of the game and that means involving stakeholders and team members, just like testing, early and often. Easier said than done, right? Sometimes us design types get pretty protective of our work.
Ever heard this? "We're the experts. Why should we take feedback from people who don't kow design?"
There is a better way.
Adding more meetings with more people can create less work for you toward the end of a project. True story.
Invite product, design, engineering (developers), QA, and any other stakeholders who are willing to attend. This is your moment. Don't you want to demonstrate the value and expertise you offer as a user experience leader to as many people as possible? Then pack that room, and show them what's up.
Here's a simple idea that works well.
As soon as you have the preliminary results of any user testing or usability work, set up a 30-minute meeting with the above people. Take the first 10 or 15 minutes to go through the tests that you have done and your findings. Show that you are approaching this problem through the eyes of the user, and that you are addressing specific needs or problems they have.
Take the last half of that meeting to get some feedback, and whiteboard some stuff. You'll be surprised what kind of ideas you get from the team when they, too, have access to user testing results.
Build on that, and have those types of check-in meetings as often as you have new insights to share. For most non-epic projects, you might only need two or three meetings max. The point is don't wait until you're "done" with UX work on a feature. Get people in on your work ASAP.
Open yourself to fresh eyes, and incorporate the feedback you get.
Developers who are intimately familiar with both limitations and possibilities of their technology and platform will have lots of ideas to solve problems you identify.
Decision-making stakeholders will also have a lens to see why certain solutions may be recommended over others.
Product managers will have better information to write user stories that help drive the innovative process.
And QA will not be left in the dark when it comes time to run their tests and get features ready for release.
On your way to advocating for user centered design in your organization, part of your responsibility is to give everyone awareness of the data that drives your decisions. Own the user experience, and don't be afraid to include as many people as possible in your process as often as necessary.