I simply sewed a small plastic curtain ring to the back of the pointed end.
So far, the rest of the quilt hangs flat against the wall. I'd thought of tacking
the other edges down with small straight pins, but didn't need to.

Thank you nancy -great idea

I would probably just put a mini-hanging sleeve at the top point and also at the two angles closest to the top. I would then slip a flat thumb tack (not a push pin) into each sleeve. I would hold the two lower tacks so they are horizontal and push them into the wall, then pull the top up and push that tack in. Not very elegant, but thumb tacks work well for me for wallhangings.

Does anyone have any advice on how to hang a table runner on the wall that is not square on the long ends of the runner?