Human nature easily transpires thoughts such as selfishness, jealously, or hate. I've felt guilty many times for possessing these feelings. I've wondered countless times how to break through those emotions.
What helped me is the following idea. There's a saying that your first thought is what you're conditioned to think, and your second thought is what you choose to think.
I am in the process of re-wiring my brain to become the compassionate and responsible person I hope to be.
When I walk past an empty plastic bottle strewn on the sidewalk, I urge myself to turn around to pick it up despite my laziness.
When I see someone fall, I try to offer assistance, rather than waiting for someone else to be the first.
When I meet someone who is attractive and intelligent, I choose to look for other redeeming factors that may be overlooked by others.
When I pick up a frozen pizza at the grocery store, I walk all the way across the store to put it back because that's not the precedent I want to set for myself.
Remembering this saying helps me to take measurable control over the outcomes of my visceral desires. I hope with time, I can begin to displace my instinctive negative thoughts with the positives ones I've willfully created.
Congruently, the Dalai Lama says something like, "Karma, or intentional action, conditions the mind, which conditions further action."