I love this #kiteboard. You can tell. I always use this one. It deserves maintenance.
I want to start with the fins. Give all of them the same shape again. Make them shorter (less grip), too. Ah, yes, and how about streamlined edges! ;)
(1) define shape, prepare stencil
(2) sandpaper all four fins to get to the shape
(3) some coating - with colors!
(4) take care of the screws