Ditto on the FB groups - I'm in sell groups and moms groups. And the ones I'm not one my daughter (a brand new Mom) or my other families are on and they refer me when they know I have an opening. I've done Craigslist too but the creepy people seem to be multiplying rapidly there - it used to be a great resource but not at the last few years.
Most of my openings are now filled by referrals, but I think I was in denial that one child was leaving (her mom is one of my best friends and they're moving to Michigan
) and am just now working to fill her spot.