There are a few issues in your post that signal alarms in my mind but first off, Welcome to the Forums ^^ hopefully anything I can say will help at least a little.

Now, are you doing this Only for her? Think about this carefully and be honest with yourself, is this something you are truly interested in & enjoy or is it more for pleasing your girl and you get some satisfaction because you are trying to make her happy?

I only ask cause this is a situation that reminds me of Pearls Before Ponygirls..

Just think about it is all Im saying, you want to be true to yourself you know.

As for how to help dominate her, there’s lots of help and advice to be found here and for starters, How do you want to dominate her? How much control does she want you to have? How much control /can/ she give you and how much /can/ you dominate her?

What aspects of bdsm is she more into over others? Does she like pain a bit more, is it the humiliation? Does she like bondage? How much bondage? Does she like power play, commands, slapping, behavior restriction? Is it only during sex or outside of bed as well?

Theres so much to explore here, but I think this can help specify what you need help with =)


Edit: I was looking around and came upon an interesting site. Perhaps you might want to look into it. http://www.submissiveloving.com/maledom.html