Once you're sure it's cycled you can add fish (or a pair of fish or group), wait 3-4, weeks, add another. Once you add one, you can buy another and place it in your QT for 3-4 weeks.
If you plan on adding a same school of something, wait at least a few months after the tank is cycled, then add the school. and wait a few months before adding anything else.
remember to keep an eye on your levels after you add fish.