To get good results in a nano tank, you should have a scale of at least one pound of live rock for each gallon in the aquarium. You could do otherwise, but be sure to remove all fake decorations. These can make your aquarium up to three times as cramped per half a pound. Also, I recommend for starters in coral rich environments pulsing xenia and various zoanthids.
Bubble algea and emerald crabs are also good for nano reefs. Plus, be sure to keep snails.