Befriend The Sprites
Trying to make friends with the Harvest Sprites? An easy way to make them like you is to give them the herbs on the beach from spring to fall. In located very close to their house (behind the church) and they love them. You'll be playing with the gnomes and having them do your work in no time.

Crash the game
At 4:44 (you can find out the 3rd digit by having the clock in your house) if you watch TV the text window will keep popping up and you cannot move.

Secrets:

Marry the Goddess
Catch all the different species of fish, including the 6 Kings

Ship at least 1 of every shippable item

Collect all 9 of the Goddess Jewels and receive the Goddess' Treasure

Own the Big Bed for your home

Dig up every type of ore from the mines

Be in your 5th year (or later) on the farm

The Goddess has an invisible love-heart and there are a few things you can do to help raise her affection for you. When you do certain tasks 10000, 100000, 1 million, or 1 billion times she'll pop out and congratulate you. You can catch fish, have steps counted on your Pedometer, or ship crops. After that, throw the blue feather in her pond, and if her affection is high enough, you can marry her.

Untrigger events!
If you want to stop events from happening when visiting houses or places, simply hold any item on your hands and enter it. By doing so, events (especially rival heart events!) that should happen may or may not happen