My hibiscus is beautiful but will not bloom, it is about 3 years old,

Is the plant a Tropical Hibiscus or a perennial Hibiscus?

Mine is a three season, which I have been growing inside during the winter and moving outside in spring/summer/fall. However it has gotten too big for my living room and I will be moving it outside permanently this year.

I have blossoms EVEN IN JANUARY. My secret?

I use Miracle Grow every other week!

It can depend on how young the plant is as young ones take awhile to re-bloom. Here's a great useful link: http://www.exotic-hibiscus.com/newsletters/july2013.htm#article2

Put some epsom salt on the dirt all around the plant and then water. This has been my go to for years.