When you get your first cow start it's name with a heart symbol and it will give good milk and grow up fast.
Wait until one of your chickens lays an egg directly above the shipping box. Water the egg and it will turn into a block. Now pick up the "egg", and you will have infinite eggs, and lots of money!
Capitalize the first letter of your name to grow eggplants and carrots. Leave the first letter of your name lowercase to grow peanuts and broccoli. To grow all of the above, make the first letter of your name begin with a symbol, such as a heart.
When you start getting eggs from chickens, use your waterering can and water the egg above the shipping box. The egg will turn into a block. Pick it up and you'll get an egg. (Repeat as many times as you want)