1. Wrong: While last week I felt pretty sickly, today, I am good.
Better: While last week I felt pretty sick, today, I am well.
Explanation: Both verbs in this sentence are linking verbs, so they need to be completed with adjectives. The first clause basically says, "I was sick," while the second one uses well as an adjective meaning healthy.
2. Wrong: Reese looks prettily in that dress.
Better: Reese looks pretty in that dress.
Explanation: The verb looks is being used a linking verb in this sentence, so pretty equates with Reece.
3. Wrong: Do you think the soup tastes superbly today?
Better: Do you think the soup tastes superb today?
Explanation: Tastes is being used as a linking verb in this sentence, so the sentence basically asks if the soup equals or is superb.
4. Wrong: The team's cheer sounds loudly in this echoey room.
Better: The team's cheer sounds loud in this echoey room.
Explanation: Sounds is a linking verb in this sentence, so it needs to be follows by an adjective.