by contributing to a good cause, either monetarily or by spreading the words in FA or around you.

just a few words about some actions I heard about recently which are a good way to improve the world and give a good burst to your karma:

first the ALSA (Amyotrophic lateral sclerosis Association) is collecting research funds to find a cure to that neurodegenerative disease.
Onkle Uncle Kage did the Ice Bucket Challenge and donated to that cause!
You can't just let that old cockroach do that without doing something too, do you?

Also have a look at another action supported by  pinkNfurry to help research in PCOS (Polycystic Ovary Syndrome),
she is doing a fundraiser with lots of participating artists,
please read her journal for more info, you can also simply donate directly.

of course these are only a very small parts of all the existing and current fund raising actions,
so if you are supporting another good cause of which you want to make people aware, just let me know and I can talk about it.