This is a HUGE maze. It's easier to think of it in sections.

First, you just want to get over to the town area. If you have the sewers open, use them. If not, follow the trail around the grid to get there.

Now go on the grid from the roof of the town. Go across to the hook.

Now go up and around, jump on trampolines and get up into top. Fall down into center, and grab shine.

Super Mario Sunshine Walkthrough