as i first time dom myself i have found that the best way to get advice is to just read what other people are doing, get some ideas on how u think u might procceed in you own relationship, if u feel like u want to be in charge of this sub, then start by bein forceful with her, let her call u master and the rest will come naturally, my best advice to new people is to take things naturally, plan a safeword so u can fully explore both your limits without things becoming awkward, communication between doms and subs is important so talk to each other about what u each want and go from there,

best of luck with the lifestyle and enjoy =)