A bigger pot would probably be the best place to start. In the meantime, some pruning to shape would be fine here. (Cut off the stuff furthest to the sides to kind of make it round.) In early spring, cut back pretty much all the side branches and leave like 3 canes, so it can grow out and refresh.
That and a good amount of light should help it push flowers. But, don't put it straight out in full sun from being indoors. It'll fry. Gradually introduce it to more light each week. Plants are sedentary. They can't adapt to sudden changes like that.