If you're not interested in optimising, just play and have fun. Outside of two cutscenes in the first year, you won't miss anything. Everything is doable just as easily in year 20 as year 1.
But if you are interested in optimising...
- Don't let your farm get too big too quickly. You'll spend all your time watering.
- Fishing can be amazingly lucrative in the single player early game.
- Mining should be your primary activity until your farm is automated.
- Don't donate your first dinosaur egg or your first prismatic shard. You'll get more.
- Basic sprinklers are a trap. Wait for quality.
- Berries are great first year crops. Especially in 1.6 given the addition of a new way of processing them. But don't forget to grow a bit of everything.
- Resist the temptation to build a glorious hoard until the second year. Profits and bundles are the most important things in the first year.
- But that being said, never sell resources. Don't be afraid to buy them either (especially in the first year).
- Check the travelling cart every Friday and Sunday. High value items are red cabbage, rabbit's feet, and truffles. Getting these from the cart instead of producing them yourself will greatly aid in getting the bundles done earlier.
- make sure to plant a pomegranate and apple tree as early as you can manage in summer. Plan for a pig before the second week of fall.
- Fish are seasonal, and appear in different locations. However, outside of the legendary fish, none are unique to spring. This means you can delay worrying about fish bundles until summer. But you can't miss any more seasonal fish after that.