Aside from instilling good principles of character (truth-telling, responsibility, the value of hard work, kindness, charity, etc.), focus on teaching your children how to think well rather than what to think. Once they have reached the age of reason (this will vary a bit on a child by child basis), there is no harm in exposing them to the various religious belief systems and letting them come to their own conclusions. However, before they have attained that degree of maturity, I would keep an eagle eye out for people with an agenda trying to convert your kids. When my son was young, I had occasion to fight rearguard actions against certain well-meaning adults who thought my parenting was incomplete because we were a secular family and needed their 'help'. Usually, one firm conversation sufficed to put a stop to that.
I can't recall any bad social situations that arose as a result of our secularism, so I don't have any advice there. Most religious children, in my experience, aren't pushy douchebags about it -- unless they are hardcore fundamentalists or Evangelicals, in which case your children might naturally avoid them out of disdain anyway.
I can't recall any bad social situations that arose as a result of our secularism, so I don't have any advice there. Most religious children, in my experience, aren't pushy douchebags about it -- unless they are hardcore fundamentalists or Evangelicals, in which case your children might naturally avoid them out of disdain anyway.