When you first start the game, you’re most definitely going to want to clear out some space on your farm. If you didn’t know, when you first arrive at your new farm, it’s completely covered with stones, pieces of wood, trees, and lord knows what else. You can clear as much as you can before you run out of energy, and then craft a chest as soon as possible (to craft a chest, you must have 50 wood). After that’s all done, sleep, and then buy as many parsnip seeds as you can carry.
At about this time, you’ll also get the Bamboo Pole from Wily at the dock, and then you can start fishing. What I recommend you do is nurture your plants every morning, and then spend the rest of the day fishing. (In my experience, fishing at the dock nets you better fish, but idk for sure).
Keep doing that, and then once you’ve got a decent sum of money, you can buy better seeds, which net more profit. Take note that these better seeds take longer to grow, so plan accordingly. When you buy a seed, it tells you how many days it takes to fully grow that plant. (For example, parsnip seeds take 4 days to grow fully.) If you plant a Spring Crop, it’ll die when Summer arrives (unless you have a greenhouse, which comes much later in the game).
Make sure to also build your relationships with villagers as you go along your day. Some of them you can only be friends with, while others might be a potential candidate for your “life partner”. Relationships are very important, and you can tell your relationship with a villager by checking how many Hearts you have with them. Something good might happen if you reach the max relationship status with them.
That should get you started on the first little bit of the game. If you have any questions, feel free to ask me anything, I’d be absolutely more than happy to help!