Use THE with:

Oceans, rivers, seas, gulfs, plural lakes

The Red Sea, the Atlantic Ocean, the Persian Gulf, the Great Lakes

NEVER use THE with:

Singular lakes

Lake Michigan, Lake Arrowhead

Mountains

The Rocky Mountains, the Andes

Mounts

Mount Rushmore, Mount McKinley

Earth, moon

The earth,  the moon

Planets, constellations, galaxies

Saturn, Mars, Orion, Andromeda

Schools, colleges and universities when the phrase begins with school, etc.

The University of Chicago, the University of Florida, the College of Arts and Sciences

Schools, colleges and universities when the phrase begins with a proper name

Fullerton College, California State University, Harvard University

Ordinal numbers before nouns

The First World War, the seventh chapter

Cardinal numbers after nouns

World War one, chapter seven

Wars (except world wars)

The Crimean War, the Korean War

Countries preceded by New or an adjective such as a direction

New Zealand, South Africa

Countries with more than one word

The United States, the United Kingdom, the United Arab Emirates

Countries with only one word

Argentina, France, Spain

Historical documents

The Constitution, the Magna Carta

Continents and states

America, Europe, South America

California, Texas, Atlanta

Ethnic groups

The Indians, the Aztecs

Sports

Baseball, basketball, tennis

Abstract nouns

Love, freedom, happiness

General areas of subject matter

Mathematics, biology, history

Holidays

Christmas, Easter, Thanksgiving