Selling is a real life skill. Everyone sells. We sell things, we sell who we are, we sell our ideas. We're always selling. Which is why it's so strange that the biggest mistake made in the business of selling (even by salespeople) is so universal. Lack of empathy. The understanding that what might seem important to you is not necessarily important to the person you are selling to.
I say this because, as Seth says, selling ideas is a fundamentally different business than having ideas, and in the current climate selling the right ideas matters like never before. Ideas are one thing, action quite another. Right now there are people sat inside organisations trying to sell in new ways of doing things. Trying to convince people to take a leap of faith. And that's not easy because faith is a very personal thing and so in order to have it, people have to get there themselves. So if you're one of these people, the best thing you can do is to recognise that not everyone has been on the same journey as you. It's easy to forget this, get frustrated, lose your passion. But if you believe in an idea strongly enough, then don't give up. Reframe it, repackage it, keep going. Because now is when we really need the great ideas.