How can you make your ERA go down?

Answer 1

Pitch more shutout innings - that is, innings where you don't give up an earned run.

ERA is calculated by taking the number of earned runs a pitcher gives up, dividing it by the number of innings he/she pitched, then multiplying the result by nine. So, for example, if a pitcher has six complete innings and gives up two earned runs, their ERA becomes three (2 divided by 6 is 1/3, 1/3 multiplied by nine is 3).

This works over the course of a pitcher's career, so if a pitcher gives up six earned runs over six innings in one game, his/her ERA becomes nine. If he/she then pitches a complete game shutout (nine full innings, no earned runs) their ERA drops to 3.6 (as it is now six earned runs from fifteen innings).