Here are some useful phrases for making requests :

– Could you help me ?
– Do you mind … ?
– Would it be possible to … ?
– Could you possibly … ?
– I’d appreciate it if you could …

Here are some useful phrases to say that you are grateful :

– Thanks a bunch / a ton. (thanks a lot)
– I really appreciate it.
– I owe you one.
– I am so thankful.
– That’s very kind.