I give a lot of credit to @rangerrebew for that. Some of the stuff he posts is from sources that are kind of on the wacky side but it at least gives perspective.
Debunking and researching fake or questionable news is also a good intellectual exercise. I'm always very proud of this site when I often see a bogus story posted that other sites like (cough cough) blindly accept without question, people here are quick to research and debunk.
The same goes for liberal leaning sites. Not only is it helpful to debunk or find out what parts are truth versus spin, but it always helps to get as many perspectives as possible, if anything, to know why an opponent is wanting to steer you one direction could make you ask and look into 'why' and what they are trying to not get you to look at.
The other thing is having your perspectives challenged is a good way to ensure you don't fall into the confirmation bias trap. Blindly believing only what confirms your initial beliefs and rejecting what doesn't. Often the truth lays somewhere in the middle.