Rune Factory 3: A Fantasy Harvest Moon

When you run out of RP in a dungeon area, leave immediately. It's not as severe as in RF1, since in that one if you lost all RP and HP in a dungeon, game over. In RF3, you just get knocked out and get teleported to the hospital.

Talk to everyone at least once a day. That's the best way to learn about events, what they like and hate, and so on. Once you hear an event mentioned (someone's birthday, a contest, etc) it gets marked on your calendar.

Keep failed foods and cans/boots that you fish up, at least a few of them. You'll thank me later once you learn what they're for.

Stock up on wood! Chop those stumps and sticks and put them into that wood storage shack. Upgrades for your farm will require lots of it.

When the time comes to catch your first monster, I'd like to nominate the elephant as a strong candidate of interest. He won't produce anything for you like the cows or the woolies, but he'll water your crops for you every day. I named mine Dumbo and he is the hardest worker.

Don't worry about time at all. There's no evaluation period or anything after a couple of years and none of the villagers are in danger of leaving, so feel free to set your own pace.

Seeds can be planted in 9x9 grid if you hold down the button with a stack of 9 seeds equipped. This also goes for anything you apply to a field (Greenifier, Formula A/B/C, etc.)

You start off with teleport spell that lets you teleport back to your house or out of dungeons, it's very useful.

Doing requests are a great way to get rare materials or better gear early in the game.

If you sell a high-quality seed, then the shop will also upgrade the seeds they carry to be that quality. High-quality seeds result in high-quality crops, which cook into better food, and sell for more money. You get high-quality seeds by using the scythe on a ripe crop. This will destroy the crop, and get you a quality seed instead. Sell that seed, run straight to the shop and then you can buy better-quality seeds. It's like permanently upgrading your ability to grow that crop. This is, as far as I recall, never explained unless you get extremely lucky in what a random NPC decides to tell you.

There are plots of land in each of the four seasonal dungeons with colored grass growing on them; these can be used as farm plots to grow that season's crops, if you find yourself needing a Spring crop in mid-Fall.

Grow onions in Spring. They're slow-growing & not super profitable, but they're used in a ton of mid- to late-game cooking recipes & you'll be glad you threw a couple stacks in your refrigerator vs spending a week running to the forest to grow them out of season when the time comes and you need them.

Buy recipe bread every day. It's relatively cheap and crafted objects make exponentially more money than raw ingredients. Cooking bread is generally given as a reward for coming in the top 3 of any seasonal event & therefore less of a priority, but it isn't a bad idea to buy a few to burn through the various grilled fish & sashimi recipes.

Seasonal harvest events are on the 28th of every season; make sure you have saved at least one crop to enter with!