I can't really suggest equiptment, as the way I handle my tanks is VERY different from most people when it comes to maintenance and equiptment. As for corals, don't add any until your system has been stable for at LEAST one month (meaning 0 nitrate/nitrite/ammoina idealy 0 phosphates as well etc) better if its been longer though, corals are sensitive. As for types of fish/corals... thats all up to you, it comes down to personal tastes, just keep in mind alot of salt fish don't do well in that small of a tank, so be sure to find out what the minimum requirements for the fish you are looking to buy are (I personally rarely house a fish in its "minimum" but I try to strive for healthiest/longest lifespans/reaching maximum size/etc for my fish).
