Armchair Critic
An armchair critic is the one who gives many advices but never tells if it could be done any better.
At The Top Of Your Voice
When you talk at the maximum pitch of your voice, that is the loudest, you can then this idiom is used.
A Still Tongue Keeps A Wise Head
This idiom is used when the importance of silence is to be preached. It is said that wise people listen more than they speak i.e. they speak very less.
At Each Other’s Throats
When people are fighting or competing vigorously then we use this idiom.