I worked full time,so it was hard to attend classes etc. I was lucky to have lots of neighbors with young children, we used to sit in the front yard and wave, then invite the neighbors to come and join us. It then became a Friday, sat and sometimes sundy night gathering.
Once our child started kindergarten at the neighborhood school, we really met a lot of parents. Volunteering brings lots of parents together. Every once in a while a parent would have a gathering or party for adults and invite the classroom parents. That was a great way for the dads to also meet friends. Consider once you find a group to hast some cookouts or happy hours too.