Reading is always a good beginning. Though it's fiction, I suggest Anne Rice's Sleeping Beauty trilogy. I can honestly say I learned a lot about myself when I read it.
I'd say figure out why you want to be a sub or what you are wanting out of it.
Some subs are seeking the mental shelter of a stronger character - the protected feeling being submissive will afford...hypothetically this could be accomplished in a nilla relationship. Others are wanting to bottom in a kink relationship but don't neccessarily want it to go outside the bedroom. And then there is the other group made up of strong individuals who kick ass out in the world, but who just happen to enjoy eating out of dog bowls and wearing handcuffs in the privacy of their own home.
Finding what will make you happy is easier when you have an idea of what it is. Before ever attempting flesh to flesh we each need a solid idea of what we want from the relationship and what we can bring to it...and try to be honest about that with the other person.
What about those who do NOT kick ass out in the world, but are ineffective and meek, yet still enjoy frequent humiliations and beatings? Let's not leave them out! For how else would a gnome get a$$?