Grow your own crops! You can sell them back to an NPC, but you may find it more lucrative to sell to other players!
1) Purchase seeds from the seed shop
2) Purchase a hoe, and watering can from the general store.
3) Find a spot to grow your plants, and use the seeds.
4) If you have some, use fertilizer to speed up the growing process, and increase your yield.
5) If purchased, you can use a plant trimmer to increase your yield.
6) Harvest your plants! (Be mindful, there is a skill check, and you can damage your plants)