90% of a star's lifetime is spent in Main Sequence, and this is the stage our sun is currently in. During this time, the star slowly increases the rate at which hydrogen is fused into helium until the core runs out of hydrogen. Smaller stars burn much more slowly, resulting in a dimmer red color. Large stars burn through their hydrogen much faster and appear bright blue, but have a shorter lifespan.
The stages after main sequence vary depending on the size of the star.