When you’re brainstorming ideas for a product or marketing campaign, you probably turn to other knowledgeable experts on the subject.

The drawback is that the people who are closest to a problem are usually too invested to identify the underlying issues and potential solutions. Plus, when you only invite the usual subjects, you’re vastly limiting your scope of ideas.

Instead of taking this general brainstorming approach, adopt an ideation process to generate innovative solutions. Take into account the collective input of the people involved in a project, and draw in the perspectives of “wildcards” — those who don’t have a stake and can offer unbiased opinions.

The key is assembling a group of people who are as diverse as possible. Once you have a team with diverse interests and backgrounds, you can follow these rules to extract the best ideas:

1. Make the Phrase “Yes, But” Off Limits

During typical brainstorming sessions, someone will present an idea for a solution, and someone else will immediately respond with, “Yes, but we tried that before, and it didn’t work.”

Instead, encourage your team to build on one another’s ideas by responding with “Yes, and,” then adding their own thoughts. You can practice by asking the team to discuss something unrelated, such as plans for the evening, and require that they add to others’ ideas by beginning their ideas with “Yes, and.” This approach takes practice, but it’s worth it. Deferring judgment is critical to ideating. Sometimes, the craziest ideas are at the root of innovative solutions.

This doesn’t mean you should undermine the importance of vetting great ideas. Just save your judgment until it’s time to choose a solution so every idea has the opportunity to blossom.

2. Create the Right Environment

Nothing says radical inspiration like a dull office conference room, right? OK, maybe not. You should find a more creative space.

We recently held design thinking sessions for clients and employees in Dallas, Chicago, and New York City. We Googled “creative meeting space” plus the city name and found many options, including Catalyst Ranch in Chicago. If you’re confined to a conference room, give it some energy with music, interesting decor, and a different furniture configuration (or no furniture at all).

Part of creating the right environment is making sure people feel comfortable expressing their ideas. Throw out some ridiculous ideas of your own so others know it’s OK. The traditional brainstorming adage that no idea is a bad idea is wrong — some are terrible. Just follow the “Yes, and” rule, and the responses will always be supportive.

3. Add Constraints

That’s odd advice for ideating, right? Trust me; constraints reap rich ideas. Here’s how it works:

Do your first round of ideation. When all team members have exhausted their ideas and written them on sticky notes on the wall, say that you’d like to do it again — but this time, all ideas have to cost at least $1 million. For the next round, require that all ideas get them in trouble with their boss, and perhaps the next one has to have an element of science fiction.

Add whatever constraints you’d like. What’s interesting is that these constraints are actually liberating. They allow everyone to step away from the norm and present a few wild ideas. It’s amazing how many times the final product has at least an element of one of the crazy ideas.

4. Mobilize Your Team

If you’re following a design thinking process, you do empathy interviews before ideation. For that critical step, you’re naturally mobile, moving to wherever your users are.

I did a design thinking exercise for an airline and San Francisco International Airport. My teammate and I walked miles getting the best interviews from a variety of travelers. If we had stopped after gathering data, we would’ve lost momentum. Instead, we went straight to our studio and met with other teams to begin ideation. We remained standing — even pacing and sometimes jumping — to keep our energy up. There is a time for rest and deep thinking, but it’s not during group ideation.

Rather than sitting down, have your team stand. They’ll be more engaged when they’re standing, and the energy and excitement in the room will naturally build. Doing this will also reinforce the feeling that everyone’s ideas are equally valid, regardless of a person’s role or background.

For more tips on ideating revolutionary concepts, read “Creative Confidence” by David and Tom Kelley. David is the founder of the Stanford University d.school, and Tom is a partner in IDEO, which designed the Apple mouse. Their ideas vastly influenced the way we approach innovation and design thinking.

As a marketing leader, it’s on you to lead effective ideation sessions. By bringing in a few new faces and creating the right environment, you can inspire breakthrough ideas.

This article originally appeared on iMedia Connection