Well some ways are

Just playing the game/being good.

Creating and selling textures for people
Creating and selling signatures/avatars for people.
Which is done here: http://forum.toribash.com/forumdisplay.php?f=371

Or doing surveys and stuff located here: http://forum.toribash.com/tori_survey.php

Another final option is buying toricredits via paypal or some other payment method available on the page http://forum.toribash.com/tori_depositcredits.php

Hope that helps.