Email is hard. It's so easily abused and can be an enormous time suck. Here some quick tips that I've been trying to implement over the last couple months:
1. Unsubscribe from any newsletters you haven't read in the last month. The information won't disappear if you don't read it. If it's important, you'll run into it somewhere else. More emails is more noise; kill the noise, be realistic about how many newsletters you can read.
2. Use Unroll.me to manage newsletters you want to read. This tool bundles all email newsletters into a single daily email, reducing noise throughout the day.
3. Setup Gmail filters for any transactional emails that you never actually read. Credit Card statement notifications and Amazon transactional emails were the biggest culprits for me.