-First things first, Stock up on sticks, wood, iron nuggets, and other stuff for material
-Hit money rock every day.
-ALWAYS pop a balloon you see. They may carry a good amount of bells
-Sell fossils (ones you do not wish to donate)
-Some things may sell better as DIY, like old tire into stack tire
-rare, if not somewhat expensive fish from Tuna/Blue Marlin to Red Snapper (a good 2,000) but save them for CJ. Same with bugs and Flick for an extra 50%
-Can't go wrong with bell trees. Plant 10,000 after you dig up a gold spot
-Always buy a bunch (or just a few) turnips on Sunday. Make sure to keep checking because even if you buy for, say, 91 and sell them for only like 120, it's still profit
-Nook Mile Tickets get you to deserted island, but you may find that are... unique. For example, you may stumble upon an island filled with tarantula, or one with five money rock in the center. They are rare, but take advantage of them when you DO find one
-Lastly, be wise with your spending. Some of the prices in Nook's Cranny have been seriously high after they expanded to the second state... so only buy something if you REALLY want it