Remember that this plant is a native of tropical forest/jungle of Africa - humidity plays a key role. I have had an off-again on-again history with dracena. None of the ones I have had ever bloomed. None of the dozens of them at work (which are professionally maintained) have bloomed in the 6.5 years I have been there.
What I remember reading about them, especially the fragrans, is that they only bloom on mature plants. I'm not quite sure what qualifies as mature, but unless it's fairly old (say 5 to 6 feet) then it probably isn't mature. Then they need high humidity, bright light, no middle of the day sun, and they hate tap water (the flouride).
The only ones I know of that bloom spend at least part of the year outdoors in some nice humid place, or are grown in a greenhouse.
Hope this helps. but like I said, none of mine ever bloomed

I think it is because indoor conditions just aren't good enough.
Now someone will post how theirs blooms every year indoor.... if so, tell us your secret to getting them to bloom!