I think it's just about time? The first 'things' are always hard though--first Christmas, first birthday, first Father's Day or Mother's Day. First anniversary of their deaths. And sometimes I'll see something and want to tell my mom or dad about it and it's like, oh wait, no. Then the sadness hits all over again.
But some days are really good days too! And those I think are the ones you have to hold on to.