is it a named variety? some trees fruit more easily than others. Standard advice is to constrict the roots, my tree is in a pot, and I prune it back hard every two or three winters. If you prune while its growing, it will bleed a lot of sap, like a grape vine. It will shoot again next spring and if it is going to produce figs you will see them appear. Sometimes they will grow and ripen in one season but more often they will overwinter. if this is the case, leave the ones that are about the size of a pea and pick off anything much bigger as it will only rot. While it is growing, keep it well watered and I use tomato fertiliser on mine.