Overshare! Overcommunication is better than a breakup. (Lack of communication and internalized bisexual erasure caused the worst breakup of my life.)
Say "I love you." Being afraid to be the first person to say it in your triad/group/relationship may mean that you say it too late or don't get to say it at all.
Check your assumptions. If you find yourself internally defining how a person might be feeling or why they might be acting a certain way, ask them instead!
Share your love! If at all possible, be out about your sexuality and your relationships with the people you love and who love you the most. (This video helped me a lot!)
If you're bisexual and/or polyamorous, be out and proud if you can so that we can raise awareness of ourselves as a community and fight harmful attitudes and stereotypes.
Being bi/poly is still hard, not everyone is going to be out without consequences, but the more we fight the easier it will get