Miraculous indeed that it survived a dark corner for years! Don't be afraid to give it too much light; the more direct sun the better. Water it as soon as the surface of the soil feels almost dry. In good light, I would expect that to be weekly. Make sure water doesn't collect in the bottom of the outer pot.
Give it a single shot of fertilizer at half strength, but don't overdo it.
Yes, prune back the bare stems to give it a fuller, more compact appearance.
Keep up the good rescue work!