A short primer from Franklin Veaux of More Than Two:
I have found that it's quite easy to locate partners willing to accept polyamory. In fact, in all honesty, I have to say "no" far more often than I say "yes."
Here are the things I have found that work to help make it easy:
1. Don't pre-script what the relationship will look like ("it has to be a polyfi triad with a bisexual woman," "it has to be a quad with a married couple"). Be flexible and open to connections even if they don't form the way you expect.
2. Don't go around scoping out everyone you meet as a potential partner. Go about your life doing what you love and expressing your joy. When you do this, people tend to be attracted to you.
3. Be open about polyamory, without apology, fear, or shame. If you are not open, you could be in a room with 15 other poly people, and all of you might be thinking "gosh, where can I go to meet other poly people?"
4. Focus less on what you want than on who you are. Seek to build in yourself the qualities the kind of person you're looking for might find desirable. If you are looking for people of integrity, be a person of integrity. If you're looking for people who are flexible, be flexible. If you are looking for people who are compassionate and kind, be a person who is compassionate and kind.
5. Don't treat people as things. Don't consider new relationships disposable. (This is a lot harder to do than it sounds.)