Real life example how use Google Analytics to improve UX

I'm currently working as a visual designer for a small startup and because we are really small we don't have money to hire UX expert, so I'm trying to do UX as well.

We are measuring many kinds of data about customers with Google Analytics and with cca 1000 UIP/day and 2 years on the way, we have quite a huge data database.

My question is: Are there any general use cases or examples how to use these data to improve customers flow? Or at least which data I should look at? Which data could help me to find week points?