A perfect relationship is not easy to describe, but if I had to describe it? Well, I'd say that a perfect relationship is when you feel on top of the world with this person, and when you feel like you're the luckiest person on Earth when with your partner. The perfect relationship is when you KNOW it's right, and when you're with that person, you're sure about how you feel how him/her, and you want this person in your life forever.
Apart from feelings? Well, I'd say that you'd have to be comfortable with this person, and if anything were to happen between you, (if you two broke up) you'd still remain friends. I hope that was okay, I'm only 12! :p