Editing Tip of the Day: Filtering

If you're revising, there's a good chance you've heard writing professionals talk about cutting out filter words. Filter words are words that authors insert that distance the reader from the scene. Instead of telling a reader what the character is seeing, for example, an author has the character stop the action to tell the reader what they're seeing. Filtering might look like this:
I saw the cat race through the hallway.
See how instead of describing what I saw in the moment, I'm stopping to talk to you as if you're here? That's part of why filtering words are such a problem. They can break the flow of the narrative and break that fourth wall, if you'll pardon the metaphor, reminding the reader that they're reading a story.
So how can I fix it? Start by eliminating the "I saw" portion and focus on the character's perceptions instead. That might look like this:
A white and gray blur tore down the hallway, leaving shredded blue strands in her wake.
Not only have I eliminated the filtering language, I used much more descriptive language, which is hopefully more interesting than the original. And as a bonus, you might get the impression that I'm a bit annoyed with my cat tonight. Emotion+description makes a more interesting passage and engages the reader, which is always the goal.
So.
An easy way to find filtering words is to look for the 5 senses, as well as things like "she thought/realized/understood."
To fix up filtering passages, eliminate the "I saw/heard/etc" portion and simply tell the reader, in the POV character's voice, what they saw or heard.
Personally, I don't believe you have to eliminate 100% of filtering language. Most of it, yes. But there are times where a straightforward, shorter sentence is better. Try to use filtering language sparingly, and mix it up with more interesting and active language to keep your readers engaged.