Do you know the charms they selling at shrines and temples in Japan ?

They're generally very small bags made ofwith beautiful cloth and have papers or something with holy power inside.

After that, I knewBecause of that, I found out that I should have returned shrine charms to shrines, and temple charms to temples.

I think that some of Japanese make such apeople make the same mistake as I did , because many of Japanese people aren't religious.

Charms

You are talking about charms as a category of things, ie multiple charms, so we would use the plural here.

Do you know the charms sellingthat are sold at shrines and temples in Japan ?

You could also say "for sale at." "selling at" does not make sense, because in English this means the charms are selling something, rather than being sold.

They're generally very small bags made of beautiful cloth and have papers or somethingartifacts with holy power inside.

Generally, it is good to avoid the use of "something" when a more specific word can be used.

My mother likes these charms sovery much.

Adding "these" helps to clarify that your mother likes all of these

Now, there are sovery many charms at my house.

You could also use the word too, "too many charms", which is means that there are an excessive/unnecessary/undesirable amount of charms.

After that, I kThere, I learnewd that I should have returned shrin these charms to shrines, temple charms to templesthe temples and shrines they came from.

I reworded this to emphasize that you are returning the charms to their respective places, not which ones go to temples vs. shrines. Instead of saying "after that I knew" we can use the verb "learned" which means to get new knowledge.

Exactly!

I would omit this--I'm not entirely sure what it is supposed to convey. It sounds extremely informal.

I think that some of Japanese make such a mistake as I did people are not aware of this because many of Japanese people aren't are not religious.

Do you know about the charms they selling at shrines and temples in Japan ?

So yesterday, I returndonated them to the nearest shrine fromshrine closest to my house.

After that, I knewdiscovered that I should have been returned ing the shrine charms to shrines, and temple charms to temples.

Exactly!

I think that some of Japanese make such a mistake as I did people make this mistake because many of Japanese peopleus aren't religious.

Doid you know that charms sellingare sold at shrines and temples in Japan ?

My mother likes charms so mucha lot.

So yesterday, I returned them to the nearest shrine fromshrine nearest to my house.

After that, I kI learnewd that I should have returned shrine charms to shrines, and temple charms to temples.

Exactly!

I think that some of Japanese make such apeople make the same mistake as I did because many of Japanese people aren't are not religious.

Do you know the charms sellingthat are sold at shrines and temples in Japan ?

It doesn't sound good to use "selling". That is the present participle, which is normally used to describe an action that is still ongoing ("I am selling my car right now, "I am selling my car this morning") or will happen at a specific time in the short term future ("I am selling him my car this Thursdays"). You are however describing an action that happens at an indistinct time.

My mother likes charms so muchreally likes these charms.

While "so much" is used colloquially in the matter you used it (e.g. "I miss him so much", aka "a lot" is very common) it's not really correct to use it like this. It should be used as an adjective. e.g. "you have so much anger in you". You will hear phrases like "I wouldn't eat so much", but here, there is an unstated "food" at the end, so it's still acting as an adjective.

After that, I knewdiscovered that I should have returned shrine charms to shrines, and temple charms to temples.

Exactly!

I am not really sure why you used "Exactly!" here. It does not make sense to me in this context.

I think that some ofother Japanese make such a(people) make the same mistake as I did , because many of Japanese people aren't religious.

"people" is optional in the first instance, but I do think that "Japanese people" does sound better there. But "people" is definitely not needed at the end of the sentence, since it is clear you are talking about "Japanese people".

Do you know how charms sellingare sold at shrines and temples in Japan ?

I am not sure if I am 100% correct with this, but I think this sounds a bit more clear/ natural and this is just how I would say it!

After that, I knew that I should have returned shrine charms to shrines, and temple charms to temples.

When you are only talking about 2 things you only need the "and". However, if you are talking about 3 or more, then you use a comma!
Example: ""Horses live in barns and dogs live inside."
Example: "Horses live in barns, dogs live inside, and fish live in the water."

I think that some ofthe Japanese make such athe same mistake as I did because many of Japanese peoplethem aren't religious.

You could say "the Japanese" or "Japanese people".

"Such a mistake" doesn't make sense here. I understand what you were trying to say, but I think "the same mistake" sounds a bit better!

Once you state who you're talking about ("the Japanese") you don't have to state it again. You can just say a pronoun for them.
Example: "Amy went to the store because she needed food."