First, you will draw a straight line going through a circle, the halfway circle mark isn't important, but it helped me so I included it.
Then add a small quarter circle for the island and a larger quarter circle to make the tree's trunk with the start of the palms.
Add a water line and the tree trunk. Note: when doing the palm leaves, it looks better if you make the lines faster, and then they will look more unpredictable--like leaves.
Sorry that this photo is sideways, but all you need to do now is add a little more details to the leaves, trunk, and coconuts, maybe add a bird or two, a sea star, and a small but mighty sailboat and voila! You're done!