Foster a charitable attitude and reinforce it with overt behavior.
Particularly, be kind to children every chance you get, and model good Pagan behavior for them, not in word but in deed. What I mean by good Pagan behavior is open to interpretation, of course, but a reasonable understanding of how I think about that should continue to clarify itself as I add posts in this series. The one thing I'm willing to mention here is to reinforce their sense of mystery and wonder at the world. The nature of our social worlds will seemingly conspire to squelch a child's belief in magic, but when you see it, you can nurture it with something as simple as a well-timed moment of eye contact and a subtle nod.
I should point out that I don't advocate any form of proselytizing, or in any way trying to tell children what to believe. What I am advocating is to give children license to believe in what their inner thoughts and feelings tell them is true. While that's particularly important where children are concerned, I believe that's the correct Pagan behavior toward adults too. Of course, if an adult wants to talk about what you believe, the truth is usually your best bet. For children, I find that modelling open-mindedness and making room for fantastic possibilities tends to earn deep appreciation. Listen to them with interest and don't patronize them. I believe doing so will benefit the child in any number of ways, and will strengthen your own spirit to boot.
There's no way to list the ways in which one might be charitable, but there is a simple way to find opportunities for charitable behavior. To start, make a commitment to be on the lookout for such opportunities, and try to think about that commitment often throughout the day. Do this for a week or two without acting overtly on any of the things you happen to notice as opportunities. Instead, let yourself think about what might be the easiest thing you could do to give something to a person who might need what you can give.
Random acts of kindness tend to stem from a charitably attitude, so after your week or two of the above simple observations and contemplation, make a new commitment to exercise a random act of kindness [increasingly often]. It goes without saying that the world is a better place when people are kind to one another. Most find that making an effort to be kind on purpose, as a form of charity, is unexpectedly instructive. Pay attention and let it build from there.