Some things I've learned in this lifetime so far:
Don't judge -- not the druggies, nor the prostitutes, not the pimps nor the pushers
You don't know what motivates them, and even the ones doing wrong are sometimes just confused and unenlightened. There's a difference between not allowing someone to hurt yourself or others and condemning them for their actions.
Be kind to all of the above, to the rich elite as well as the homeless panhandlers, whether you believe they deserve it or not. Kindness is not a measure of other people, it's a measure of yourself.
It's better to regret doing a thing than to regret not having done a thing. We learn best by our mistakes.
For the above reasons, forgive others their mistakes. Allow people to learn and grow. Encourage them to make new mistakes, rather than repeating the same ones of the past.
Life is a spiral. Sometimes it can seem like you're going in circles and back to where you started. Each time that happens, take stock of what you did to put yourself there. The difference between an upward spiral and a downward one is simply turning around and facing the other direction.
There is no shame in accepting help from others. Pass it on.
What doesn't kill us often breaks us. There are a lot of broken people out there. Be kind to them.
Violence only begets more violence. To have peace, cultivate peace.
Nothing belongs to you. You can't take anything with you. You keep nothing, not even your body. Everything is on loan, so take care of it because you'll have to give it back some day. Learn to share with others who respect this rule and protect from those who would violate it.
Above you, be kind to yourself.