I don´t know how good your communication skills are but from my personal experience I don´t get a lot of proper messages. Most of the time I don´t even get messages just invites to be friends with some random douchebag. I don´t know how this works out for them with other people but I seriously doubt that it leads to anything good. It doesn´t take a lot to say hi, besides if you don´t feel like saying hi then why would a Dom/Domme feel like adding you as a friend?
If you write to a Dom/Domme always be polite, don´t assume things and definately don´t go into details from the start what you want. A good idea is to first introduce yourself and tell a little bit about yourself, then you can ask some questions but for a first message it´s better to be short and to the point. What I mean with that is that you don´t talk about the weather or how much you like cats, it can be fascinating to talk about once you know eachother better but it´s not interesting to talk about in a first message.
Not every Dom/Domme finds it important that you write about him or her with capital letters. Like Him or Her, but to be safe you can start with that because some do prefer that or even demand that! Always be respectful, so it´s better to be formal than informal. Try not to be a suck up, some Doms/Dommes might like that but some really hate that. If a Dom/Domme likes that, then he or she will mention it. Don´t assume anything, get to know someone and then maybe you get an idea who he or she is. Just remember that you get to know someone as good as the other lets you.
So where do you find Doms/Dommes? Well you can find Doms/Dommes at meetings or fetish events. If you don´t feel comfortable around that many people you can find Doms/Dommes on fetish websites, maybe even dating sites if you´re lucky. A friendly reminder, just because you´re polite and friendly doesn´t mean that you get a reaction from a Dom/Domme. Maybe they´re busy, some Doms/Dommes get a lot of messages, or maybe they´re not interested. On a website try to have an interesting profile, have some pictures of you and tell a bit about yourself. If you go to a meeting or event try to look good and don´t act like a creep. That should get you further than hi how are you doing?