One of the core tenets of my personal ethics is to avoid judging others at all costs. I mean, sure, if someone is abusive or does something actually harmful, I will judge them for that, but in general, my belief is that just because someone is doing something I wouldn't do, doesn't mean they're not trying their best.
But what happens when you feel judgmental anyway?
So far throughout my adult life, whenever I recognize judgment in myself toward others I have felt intense guilt, then tried my best not to acknowledge the judgmental thoughts. But pretending that I don't judge others doesn't mean I don't. It just means I'm lying to myself about judging them and doing it subconsciously anyway.
I don't think this is very effective. People still notice when you're judging them, even if you're doing it subconsciously and experiencing a lot of guilt simultaneously. In fact, I think the guilt makes the judgment worse - it adds a layer of resentment that I have to feel guilty to the already terrible mix.
So I've come to a conclusion that sounds kind of counter-intuitive: I have to accept my own judgmental thoughts before I can let go of them. Lying to myself about having them just makes me self-righteous, guilty and resentful. It's better to honestly recognize in myself that I have judgmental thoughts, forgive myself for them (all people are judgmental, I'm pretty sure), and then consciously work to understand the perspective of the person I'm judging.