1. Don't use THE with general plural countable and uncountable nouns

Eg: She buys apples. / He is baking bread.

2. Don't use THE with names of people/ holidays/ companies/ universities

Eg: Do you know John? / They have plans for Christmas and New Year's. / I stopped using Twitter and Facebook. / When Scarlet finishes her undergrad at Oxford, she will transfer to Standford.

Exception: We do use THE when the university name starts with the word "university"

Eg: My brother will be teaching at the University of Miami next year.

3. Don't use THE with most country names

Eg: You should come to England. 

4. Don't use THE with most names of cities, towns, states

Eg: Pollution is terrible in Los Angeles./ My grandparents retired in Florida.

5. Don't use THE with names of streets

Eg: Oleg's flat is on Lombard Street.

Note: The only exception is the High Street.

6. Don't use THE with names of lakes

Eg: We'll take the kids out to Windermere Lake at the weekend.

7. Don't use THE with names of single mountains

Eg: She really wants to visit Mt. Everest.