I am not a graphic designer but I can do a few things in Illustrator.
My task is to convert the below image to a vector in Illustrator. I can do everything fine except the top blue shape. How would I do this? Any help is greatly appreciated!
I would draw 2 ellipses and then use Pathfinder to "Minus Front"
I used both these and just guessed at where the center point of the first ellipse would be.
Then Option+Shift+drag to make a copy.
Switch to the Free Transform Tool, again holding the Option key to move both sides in unison.
Finally Pathfinder > Minus Front to remove the unnecessary parts.
This doesn't match the shape exactly but it is far more uniform than the original shape, while still maintaining the desired appearance. To me, the inconsistency in the original shape seemed to be an error, not intentional.
You can use auto trace for this (as it is a basic shape)
For more accurate (and controllable) results, use the pen tool: (P)
Note: this was my 15 sec attempt at the pen tool, if you spend a few more minutes, you can get it really good
Scott's answer is correct as far as symmetry goes, my answer is considering that this shape is intentional and you are trying to recreate a perfect copy of this exact shape