Mines
Sell your gems EVERY time you go to the mine [early game only]

Always keep a chest in the entrance of the mines [not skull cavern] use it to empty your inventory for a short amount of time, and to put emergency food for when you're close to die, and to put the crap you don't want to sell or in your home. It turns out to be very useful

Items & Chests
Always keep at least 1 of every item including fish gems plant flower crop etc.

Have an assortment of chests COLOR coded to let you know where you should put your items; for example, RED chest is the FRUIT chest [resembling cherries, or apples]
LIGHT GREEN being your farming equipment [seeds & tools] DARK GREEN being your veggies, BLUE being your fish and coral, etc.

Food
LINUS is my key to food. If you get him to 6 hearts, you'll have a cut scene in his tent where he gives you a food recipe.
The ingredients are: 1 Fish
That's all! It's super cheap, and gets you good health and energy. You're able to make a lot of 'em & stock up for epic mine trips

Weapon Upgrades
Depending on what YOU want, there's 2 different things you want to upgrade first; The Ax then the Watering Can. Since the fist 40 levels of stone in the mines is easy to break, I'd recommend not going to pickax fist.

Ax upgrades: decreases the amounts of hits a tree takes [makes it stronger, essentially]
basic ax 10 hits [15 incl. stump]; copper ax 8 hits; steel 6; gold 4; iridium 2!

Watering can: increases the amounts of tiles you can water at once, and increases water capacity
basic- 1 tile; copper- 3 tiles; silver- 5 tiles; gold- 9 tiles; iridium- 18 tiles [6x3 area]


This is all I have for now, but I'll update this when I can