Seb7, The first thing I thought when I heard that Google was beta testing a new social network was this is my chance to get in on the ground floor of something huge. I paid close attention to the bigger names that I could identify with and learned a lot. I think Robert Scoble was my biggest influence. He got his large following from being a community builder across new networks. I tried to offer valuable conversation when I could and gained a lot of followers that way. By the end of the beta I was at about 1,000 followers. Then when circle sharing started it exploded.
The keys to getting the most from G+ are to remember first it's not Facebook. It's about finding new connections who share the same interests instead of BS'ing with someone from work. Second share to public if you want to be seen, posts with a photo attached and well formatted with bold etc are the best received. Third, offer verbose conversation and don't be afraid to talk to the bigger names (unless they are the type that post and run). Fourth don't be afraid to add large circle shares (you can search for them), the busier your stream is the more opportunity to connect and share.