In brief:
* Farming Mechanics and Crop Rotation strategies - Depends on if you are looking for profit, for gifting, for crafting, or for something else. You gain Farming skill points when you *harvest*, not when you plant or water. Your levels in Farming will impact the quality of crops you produce, to an extent. You are more likely to get silver or gold star crops the higher your level in Farming. Keep in mind that some crops have secondary yields, these will always be normal quality no matter the modifiers.
There's several threads on 'most profitable crop per season' you can look up for the numbers, but in general potatoes, kale, and cauliflower are high profit margin items in spring; blueberries, melons, and especially Hops if you have brewing unlocked are profitable for summer (also starfruit if you've unlocked access to the location that sells them); Cranberries and Pumpkins are good profit margin items in the fall; and if you can find an Ancient Seed somewhere, given that they grow in all three growing seasons, planting them on Spring 1 (especially on Deluxe Speed-Gro fertilizer) is more profitable than all of the above combined.
* Animal Husbandry and Breeding strategies - Breeding isn't really a mechanic per se, the closest you get is that if your barn/coop isn't full, and you haven't disabled the mechanic, there is a low but non-zero chance that you'll spontaneously get a new baby animal in the morning. As far as animal husbandry, pet and feed your animals daily to increase their hearts. More hearts means better produce. Large Milk will produce Gold Star quality Cheese instead of normal quality. Large Eggs produce gold-star quality mayo.
* Mining and Combat Mechanics - I'll just link
my guide on the topic here for you.
* Crafting and Resource Management - This is more to taste than anything. For myself, I tend to rush certain skills to unlock useful things. For example, Farming 6 unlocks both Quality Sprinklers (so I don't have to constantly manually water my crops) and the Cheese Press. Farming 5 unlocks the Preserves Jar, and Farming 8 unlocks the Keg, which are the keys to maximizing your profit margins. Foraging 6 nets you access to the Lightning Rods, which not only produce batteries during storms, but also protects your crops from getting struck by lightning.
* Relationship building and social mechanics - You can give up to two gifts per week to each villager, the benefit will be determined by how much they like the gift. Finding 'liked' and 'loved' gifts can dramatically reduce the hassle. Every day, anyone you haven't interacted with loses a small amount of relationship points, so talking to people you want to become friends with on a daily basis is useful. Figuring out their schedules is also handy so you know where they are to gift/talk to them. Giving them a gift on their birthday gives a multiplier on the friendship points earned, so maximize this by giving a high quality loved gift on their birthday if possible.
I hope this is helpful for you.
