Today morning, I couldn't get up early, so I missed first class.
= This morning, I couldn't get up early, so I missed the first class.

 I heard first alram bell, but I turned off it, then slept again.
=  I heard the first alarm bell, but I turned it off and went back to sleep.

 I have a friend whose name is Julio.

He and I met first in school, and we became friend.
= He and I first met at school, and we became friends.

Today after school, I participated in Julio's fare well party.
=  After school today, I attended Julio's farewell party.

He is going to go back to Mexico tonight.
 

 Everytime I say good bye to my friends, I think that there isn't permanent relationship.
=  Every time I say goodbye to my friends, I realize that no relationship is permanent.

So I try to accept that effect.
= So I try to accept that fact.