Typical mistake: You look beautifully.
With verbs, we usually used adverbs, not adjectives. But with certain verbs (e.g. seem, look, taste), adjectives can be used. This happens when we are really describing the subject of the sentence, not the 'action' of the verb. Verbs of this kind are be, seem, appear, look, sound taste, feel and smell.
Examples:
S/he is nice.
S/he seems nice.
S/he sounds nice.
S/he smells nice.
S/he feels nice.
But be careful. Some of these verbs have two meanings. Compare the following:
The problem appeared impossible (Not: ...impossibly).
Linda suddenly appeared in the doorway (Not: ...sudden).
In the first sentence, appeared means 'seemed', and is used with an adjective; but in the second sentence appeared means 'came into sight' (an action), so it is used with an adverb.
Look, taste, feel and smell can also be used to refer to actions, and they are then used with adverbs. Compare the following:
Your father looks angry (= seems angry).
He's looking at you angrily (looing = 'directing his eyes' - an action).
The soup tastes wonderful.
I tasted the soup suspiciously.
My skin feels rough.
The doctor felt my arm carefully.
Sometimes other verbs can also be followed by adjectives, when we are really describing the subject of the sentence, and not the action of the verb. This often happens in descriptions with sit, stand, lie.
Examples:
The valley lay quiet and peaceful in the sun.
She sat motionless, waiting for their decision.
Some verbs are used to show how the subject of the sentence changes in some way. These verbs are also followed by adjectives. Examples are become, fall, get, go, turn.
Examples:
She fell unconscious on the floor (Not: ...unconsciously...).
It's getting dark (Not: ...darkly).
Adjectives can also be used to show a change in the object of the sentence.
Examples:
The new washing machine was clothes super white (Not: ...whitely).
He pulled his belt tight and started off (Not: ...tightly...).
