Difference between "much", "many", "a lot of", "lots of"

Much - Many
Much and many are used in negative and interrogative sentences. Much with uncountable nouns. Many with countable nouns.

• Kevin don't have many friends.
• I don’t have much free time. 
• Not many of the students understood the lesson. 
• Are there many people at meeting?

Much and many are used in affermative sentences with: so, too.

• There are so many ways to write composition.
• Cinese people eat too much rice.

Much is used as adverb with: very, so, too.

• I like chocolate very much.
• They eat too much.

A lot of / lots of
A lot of / lots of are used in affermative sentences with both uncountable and countable nouns.

• There was a lot of (lots of) space. 
•  I ate lots of cookies after dinner.