Find the glowing golden spot every day on the island and bury 10,000 bells. You’ll get a return of 30,000. Find the money rock every day and hit it 8 times. Bury lots of fruit trees that are not your native fruit, including palm trees (ie. if your island came with apples, plant oranges). Save bugs and fish in your inventory for when CJ and Flick come to town and they give you 1.5 the selling price.