Just a note

Today was a long day. I mean, I finished a lot of things after work. Now I will go cycling at the park. It takes about one or two hours, after that I will return (to?) home and check for new mail; maybe someone of my friends wrote me a letters. After that I will take a shower and go to sleep. Good night!

Excellent job! It's near perfect :) Now, lets make it into a spoken statement.

Today was a long day. I mean, I finished a lot of things after work. Now, I'll go cycling at the park. It takes about an hour or so. After that, I'll go home and check for new mail; maybe some of my friends wrote me letters. Then I'll take a shower and go to sleep. Good night!

The statement about the letters can be presented in 2 ways, depending on the number of friends you are expecting letters from:

1 friend - "maybe one of my friends wrote me a letter".

The word "friend" is still plural because you are picking one friend out of a group of friends.

Many friends - "maybe some of my friends wrote me letters".

In this case, you are expecting more than one friend to write to you.

Just a note

Today was a long day. I mean, I finished a lot of things after work. Now I will go cycling at in the park. It takes about one or two hours, after which then I'll return (to?) home and check for new mail - maybe someone one of my friends wrote will have written me a letter. After what that I will take a shower and go to sleep. Good night!