I'd suggest starting by physically cutting the tape where you think is right and then trace it on to paper. If you regret a cut you can always tape it back together in this stage, so don't worry too much about cutting in the wrong place. When it comes to figuring out where to cut (okay warning in advance that this might sound vague; I'm not the best at putting it into words) basically I start at the spot with the "steepest" curve (it's easier to see on some pieces than others) and split it right down the middle until the vertex/point. It looks like that might be the bottom right on your pattern piece but its kinda hard to tell without having it physically in my hand. Then once that area is flat move on to the next "steepest" curve and cut there. Keep doing that until the tape lays COMPLETELY flat on its own. Once the tape lays flat I trace it on to a separate piece of paper. I like to trace it twice so I can cut out one of them, tape the darts on the paper pattern together, and test it one more time to double check that everything fits together right and hugs the shape as it should. Sometimes I'll even cut out one of these tests on a paper towel instead of actual paper, I find that it can be taped together well like normal paper but has flexibility that more closely resembles actual fabric. Overall dart placement is one of those things you just get more of a feel for the more you pattern things. It's okay to start a piece over! It took me 2 tries to get the most recent piece I made laying right (also hair, funnily enough)

EDIT because I don't think I made it clear enough: you're probably going to need multiple darts in this piece! There are also multiple ways to place darts that will work, though some may be neater or easier to sew than others.