In the beginning of the game, you will likely die a lot. But once you die a few times and grasp what needs to be done to survive in the beginning, it will be a breeze.
Whack down things like tall grass, crops peeking out of the earth, large, dark rocks, and loose branches.
Until you craft a weapon, avoid greyishly green slimes, Thug looking mofos with weird hats, edgy wraith things underground, and other annoying enemies that threaten your survival!
To survive the 2nd night, you should collect as many materials as you can and then build a "base" where you will be protected. Collect the food, stones, sticks, and fibers and craft a pickaxe, axe, and dagger. With these 2 tools, you can mine rocks for other ores and chop trees for resources and the dagger for protection.
(Keep a torch on you for portable light!)
If your hunger bar is getting low, remember, Shrooms are easy pickings! Until you craft a Campfire, Green and Yellow ones are what you should be looking for.
Once you have sufficient materials, craft a workbench to unlock more crafting recipes. From the workbench, you can create walls for protection, and other workstations to advance in the game.
Bone Bench contains strong bone gear that is relatively easy to make compared to the other gears, you can and should craft them before more advanced items from the furnace are available.
When you are ready, you should start venturing into the caves to collect copper and iron. Do note that the caves are dangerous and you should be prepared.
Treasure chests can be found throughout the game in many ways. Such ways include treasure fishing, daily spin, doing arenas and dungeon boss modes, defeating bosses, etc.
Fishing in normal waters won't be as profitable. But if you see treasure spots in water (some weird looking shadow shape), then rare treasure could be fished at a much higher rate.
Opening treasure chests will get your strong items to equip to aid you in your adventures.
Remember to do the quests from the "!" icon, as completing quests will get you diamonds and other cool items!
There are many bosses in the game and their difficulty varies from one to another. Remember to bring potions, healing kits, whatever you can to aid you in combat. Potions can be crafted from the alchemy table.