How to get Star Shards
Before you start using Star Shards, you need to collect some of them. This can be done whenever there is a meteor shower in your city. How do you know there will be a meteor shower on any given night? Easy, Tom Nook or Isabelle will let you know that we are coming during the daily briefing. You can make sure you get it by saving and exiting whenever you're done playing and then being extra careful when reloading.
If a meteor shower arrives that evening, be prepared for the scheduled start time. Use the right dial to look skyward, making sure not to equip all tools with the directional pad. When you see a shooting star, you'll want to hit A to make a wish. Keep your eyes on the stars and press A whenever you see a meteor cross the sky. Each time you see a shooting star repeat this, as you will receive a star fragment each time. You will only have to check the beach in the morning to find them all.
What to do with the star fragments
Now that you have the Star Shards, you might want to know what to do with them. The answer is similar to the many other mysterious objects that you will discover during your time with Animal Crossing: New Horizons. You can use it to craft new items and furniture later in the game. Once you discover Star Shards, you will start unlocking DIY recipes for items that need them, like the Moon Piece. (one of my favorites since the very first game). Collect as many of these important crafting items as you can as they are hard to get anymore and will create some really cool craftable items.
And that's what to do with Star Shards and how to get more of them in Animal Crossing: New Horizons.