Information about Shrine Etiquette
Procedures
The first thing you do at a shrine is pass through a torii 
gate. If you’d like, you can bow to it before you walk through as a sign of respect to the god(s) of the shrine. You can also side walk (like a crab) through the torii, facing the middle. In earlier ages, people did this to show they were unarmed and had nothing to hide. You should though not walk in the middle of the path and instead to the side (I recommend going with the flow of traffic as left/right side walking changes from prefecture to prefecture). The center of the path at a shrine is considered where the god(s) walk.
Once through, there is usually water to purify your hands and mouth. Normally you’d wash your left hand, then your right, your mouth/lips, and then let the remaining water wash over the scoop’s handle. You’d let this water all fall outside the basin as in the basin should be the pure water. However, nowadays because of the pandemic, the scoops are gone from most shrines and they have a small trickle of water instead.
Please feel free to contribute more shrine etiquette tips here!
Seasonal
Dondoyaki
It’s considered disrespectful to throw out New Year’s decorations and charms with the regular trash, so starting in early January, many shrines have a box where you can put old charms and spiritual decorations to be purified with fire.
Chinowa Kuguri
Chinowa Kuguri are vertical hoops made of grasses that you can usually find at shrines starting on June 30th. Their purpose is help purify and repel diseases. You are supposed to walk through the hoop 3 times as part of the ritual. First you go through and circle around to the left, then you go through again but circle around to the right, then you go through a third time and circle to the left, finally, you pass straight through.
I’ve never seen one of these without a diagram with pictures, but when in doubt, you can copy the person directly in front of you. Depending on the size of the chinowa kuguri, many people can pass through at the same time and because you are turning different directions, it can get crowded. The busiest one I’ve gone through had maybe ~15 going through at the same time and it was wide enough for 2-3 people to pass through the hoop together.
More information in Japanese:
Tips
- Don’t pass in front of someone who is praying. Walk behind or around them and try not to disturb them.