Epistemic status: rough thoughts, but the technique described has been useful for me
Suppose you know you have some bias, but also that you can't remove it. One option is to notice the bias, then try to think your way out of it - at least a little. For example, in The Scout Mindset Julia Galef suggests combating status quo bias by inverting the status quo and asking yourself if you would still make the same decision. (E.g. if considering moving from city A to city B, would you make the same decision if you were currently in city B and had the option to move to city A.) This test is imperfect but can help combat bias.
But you could also, or instead, insert a counterbias - a rule of thumb that, without the existing bias, would bias you in the opposite direction, but with the existing bias, tends to move you closer to the truth.
For example, when I am running late for a meeting, my first intuition is almost always to give the most optimistic projection I can for when I will be there. Even when I try to consider the question of when I'll be there objectively, I'm influenced by wishful thinking and tend to underestimate how long I'll take by a long way. This is the bias.
The counterbias is to give what seem like extremely pessimistic predictions for when I'll arrive in these situations. If I think I'll be five minutes late, I might say I'll be there in the next fifteen minutes. This feels wrong but is usually right. It's not always right and will sometimes produce errors, but I'm less wrong over time than if I weren't to use these techniques.
Here are some other examples I think are useful:
How do you develop a counterbias? You notice a specific situation in which you are biased, design a counterbias, test it a few times, then make it into a habit if it seems helpful.
Caveats: