When you say established do you mean post-cycle or you just set it up a week ago. If you just set it up, I would wait to ensure your cycle has already completed, then go with a mixture of turbo snails, scarlet hermits and maybe a brittle star. I hope you did not cycle the tank with the clownfish, but I digress.
As far as soft corals it depends on your lighting system that you have. If you are using Power compacts or flourescents you will not be able to keep much. Maybe with PC's you might be able to keep some xenia , but near the top. If you have VHO's you can keep almost anything except some clams. There are exceptions to every rule, but I have found xenia, blastomussa etc are pretty easy.
--Andy