You can't pay attention to everything in a newscast but what you do pay attention to says a lot about your bias and what you want your viewers to think

If you want your viewers to hate a group only show them the worst of that group. Ignore the rest. 

News Media often simplify very complicated things like the Economy, the Environment, etc. by picking only the evidence that suits their message

If your party is in power time to cherry pick evidence that the economy is the best ever. If it isn't time to cherry pick evidence that the economy is collapsing and won't survive if there is another term.

Bias is like fairness. It's easy to spot when it's unfair against us but we don't even notice if it's unfair in our favor.

If your side or candidate does something bad, ignore it. If that doesn't work then interpret in the most generous way possible then refocus on how bad the other side is

Whatever the other side does make sure you interpret it in the worst way possible

Cherrypick polls to show that your side is clearly in the majority even if it's not 

You might also like these longer videos explaining the psychology behind bias