This essential advice has been updated as a PDF. In year 2016, Lama Zopa Rinpoche mentioned two practices to focus on: How to Make Life Most Beneficial for Sentient Beings, Even with Your Speech and The Method to Transform a Suffering Life into Happiness (Including Enlightenment)
"Generally, you have to know that you are responsible for not causing others suffering, but to bring them happiness. Even if you don’t think of practicing Dharma, to at least be a good human being, you need to know this. You are totally responsible as to whether you bring happiness or suffering to others. It is totally dependent on your motivation and how you treat others; it’s up to you whether your motivation is pure or not.
Even just to be a good person, a generous human being, you have to know that. If you have a bad motivation and your actions of body, speech, and mind are harmful for others, you make others create negative karma when they retaliate by harming you in return. By harming others, you therefore cause them to be reborn in the lower realms, to lose their human rebirth and take a lower rebirth and suffer for eons." - Lama Zopa Rinpoche