"Thank you" vs "Thanks"
Thank you = more polite/formal
Thanks = casual, with friends
Both are correct!
"Excuse me" vs "I'm sorry"
Excuse me = to get attention or pass by
I'm sorry = to apologize for a mistake
"You're welcome" alternatives
No problem = casual
Of course = happy to help
Sure = very casual
"Please" placement
Beginning: Please help me.
End: Help me, please.
Both are correct!