Making big money from your farm in Story of Seasons: Pioneers of Olive Town is all about crop quality. You want to get to the point where you are producing 10 Star crops to get the most possible money, and the only way to do this is to increase the land quality.
There are a number of different ways that you can improve the quality of your land, which we will run through in this guide.
As you perform agriculture-related tasks, your Fieldwork skill will increase, and every couple of ranks you will get a bonus to your land quality level. The better the land quality, the higher the quality of products you can grow in it. This is great because it means the quality will passively improve as you are playing through the game.
Once you get access to the Shrine, which should occur roughly halfway through your first summer, you can keep collecting the Spirtes and after gather 100 of them, you can start to purchase blessings that will increase your land quality. You can purchase up to three of these blessings, and they should be a priority for you if making money is the main goal of your time in the game.
The store will only sell you basic seeds, but you can use a Seed Maker to produce higher quality seeds. If you place a vegetable in the Seed Maker, you will receive two better quality seeds, but the Big Seed Maker that you get at Level 10 in Fieldwork will transform 2 vegetables into 6 seeds.