Which preposition is more commonly used with impressed “impressed by” or “impressed with”?
1) I wasn’t impressed with or by the service in the restaurant.
2) I’m very impressed with or by her English.

Question

Which preposition is more commonly used with impressed “impressed by” or “impressed with”?
1) I wasn’t impressed with or by the service in the restaurant. 
2) I’m very impressed with or by her English.

Answer

Hi Amit,

This is your new learning friend! https://books.google.com/ngrams

It tells you how frequently certain phrases appear in literature. It's a good way of telling how common  similar phrases are.

I had a play with it, and "impressed by" is slightly more common.  In US English, the usage is even more equal to "impressed with". The really interesting thing is that "impressed with" was much more common until about 1900-1920, when both prepositions were used equally.

Answer

Hi Amit,
Michael is right!
We use impressed by when you are referring to yourself being impressed by something ( eg I was impressed by what you said ) and "impressed with" when someone else is impressed with you ( eg he was impressed with your performance)

Answer

Hi Amit

In the examples you have given (which are active voice) both prepositions are commonly used and it's a matter of preference which one to employ.

But in a passive-voice sentence you must use "with".

You impressed me by your honesty. - WRONG
You impressed me with your honesty. - CORRECT