If we decide that we are really going to improve our thought-life (the experience of thoughts), then there are a few things we need to keep at in mind (yes, there's a pun in there).
First, we must remember the admonishment from Fr. Meletios, "You are not your thoughts."
The next is to remember that bad feelings are my problem, not someone else's fault.
No one else can 'make' me feel anything. I choose to be offended, or aggravated, or resentful, or critical. My hatred or disdain for others is my own doing.
Therefore, when I experience a thought which alienates me from others, then I have an unhealthy thought that I must work on and uncover the roots of. Ultimately, at the core of this discomfort is a fear: fear is at the center of the passions, which drive us away from God.
Men who have fallen prey to their pride forget this axiom and inevitably fall victim to poisonous thoughts. Once we give ourselves permission to think ill of others, then we fall into an abyss of hatred when God is not present. God does not want us to hate one another. We are to forgive as we have been forgiven. having forgiven, we can receive His forgiveness more easily.
The hypocrite is always in danger of being uncovered and ashamed. Hypocrisy is not a place we want to be found. We always fight against it.
Before we fall to that trap, we should judge our thoughts and progress based on how we are with others, even those who hate us. Do we hate them back? Do we react with anger and contempt? If we are experiencing these negative feelings, then we are on the wrong path. These ideas must be pushed aside and their origin uncovered. We must repent of these feelings and thoughts, and ask God to enter in and heal us.
On the other hand, thoughts that bring us closer to others are good thoughts. Ones that harbor mercy, patience, and generosity are to be heeded. Thiis is the easiest 'rule of thumb' for thoughts.