Here's a few things I do. They are not fool proof and I don't always follow my own advice, so take them for whatever value you find in them.
1. Find at least two sources from left leaning media and two from right leaning media. I have my favorites on both sides.
2. Try to find original content rather than a simple duplicate copy of an AP story or two sources with nearly identical copy. There is a lot of intellectual plagiarism out there.
3. Ignore the headlines and pull quotes (the enlarged quotes of the article). These are designed only to get clicks and lead you to a biased conclusion.
4. Ignore opinions and conclusions. Anything that characterizes the facts or statements of people quoted in the story is not journalism; it's activism, designed to mislead.
5. Look for details that are common between the ideologically opposed sources. These are often truths.
6. Look for details included in one side and excluded in the other. You won't immediately know if these are true. Often they lack complete context and are included in the way that they are in order to support the characterizations being made by the writer or editorial staff.
7. Assume that there is always more to the story than meets the eye.
8. Take photographic and video evidence with a grain of salt. It is altogether too easy to edit these and remove context that contradicts the slanted narrative. I've been caught by this more than once. We want to believe what we see and hear. This is where we are all most easily manipulated.
9. Assume that all media sources have an angle, a narrative, that they are pushing.
10. Watch for stories that are covered only by one side. Ask yourself why. Dig for multiple sources. Often when a story hurts the narrative, the story is still covered but it's buried under a bland headline designed to avoid clicks.
11. Use more than one search engine. Every search algorithm has bias built in. Mostly that bias leans left, so you may need to dig deep to find opposing coverage from the right, but you will find it.
12. Distrust bloggers, podcasters, straight up opinion talking heads, and so-called independent fact check sites. Listen to them but do not believe everything they say. Research whatever they say using the steps above.
Again, this is not foolproof, but it does help me.