Sharp As A Tack
Used for very clever people.
Rest On Your Laurels
When some one rely on his past achievements rather than trying to achieve things now we use this idiom.
Pleased As Punch
When we are totally satisfied with our efforts we are pleased as punch.
To Have The Courage Of Your Convictions
Used for people who are brave enough to do whatever they feel is right irrespective of any external pressure.
Two-Faced
People who speak something on your face and something else on your back are two faced.
Yes-Man
Someone who always agrees with his superior irrespective of whether the superior is right or wrong.