Dressed to kill
Wearing glamorous clothes to impress others

Look like a million bucks
To look extremely good or attractive

The spitting image
To look exactly like someone else

Mutton dressed as lamb
An older person dressed in a style suitable for younger people

Face like thunder
To have a very angry expression

Not a hair out of place
Perfectly groomed appearance

Beauty is only skin deep
Physical appearance does not show someone's true character

Pretty as a picture
Very attractive or beautiful

Ugly duckling
Someone who looks plain now but will become beautiful later

Don’t judge a book by its cover
Don’t judge someone or something based on appearance

To have a face only a mother could love
Someone who is considered unattractive

Appearances can be deceptive
The way something looks might not reflect reality

Dressed to the nines
Wearing very fashionable or expensive clothes

To cut a dash
To make a striking impression with one's appearance

Easy on the eyes
Attractive or pleasant to look at

Down at heel
Wearing old, worn-out clothing or looking shabby

Look a sight
To look messy or untidy

To turn heads
To attract a lot of attention due to being very attractive

Fit as a fiddle
To be in excellent physical condition

To be all dressed up with nowhere to go
To be dressed nicely but have no plans or reason to go out