Don't solo all the time - it gets lonely. Take passengers and share flights with pilot buddies.
This is probably the biggest let-down for me since gaining my PPL. I often take non-flying passengers (friends and family etc) but I am yet to fly with another PPL. I think this is a real shame as it could be a great opportunity to share experience, and fly with somebody who is generally interested in the same thing, not just coming for a jolly.