As a professional Mistress, 
every day i get approached by many (slaves, subs and/or kinksters). 
The number of messages I receive can increase considerably. 
As a result, many men who approach me are only fakers and time wasters , and/or only contact me to fantasize and masturbate, so I am forced to be selective in contact. 
For that reason I have written out my general terms and conditions.

  Every professional Mistress has her own etiquette (GTC).   
I am convinced that every Mistress will appreciate it when you submit your intake form neatly and completely. 
If you introduce yourself well in the first contact, you will stand out and it will be more likely to have a good BDSM/Kink session that we both enjoy.

 1: 
Do your research 

You will probably find a Mistress on the internet; via social media or websites such as Kinky.nl. 
Make sure you not only look at her photos. More important is to read the  advertisement text carefully. 
The text often makes a lot clear about what is, and is not possible during a BDSM session. 
Almost every professional Mistress has a website. 
Read and study this carefully, so you can get to know her a little and assess whether your preferences and boundaries match. 

 2: 
Be respectful! 

Be respectful in your communication with a Mistress. 
You can often find on her website how she would like to be addressed. 
Never just send nudes if a Mistress hasn't asked for them, it's rude and there's a good chance she'll block you. 
It is also disrespectful to negotiate the price of a session. 
Professional Mistresses are valuable ; treat them that way!

3: 
Send a neat and complete ''Intake form''

Always introduce yourself politely and be clear why you are sending a message (do you want to plan a first session? Please mention this!). Briefly tell me about your current experience in the BDSM world.
Are you inexperienced or experienced? 
Share your boundaries and preferences. This way, I can immediately assess whether you are serious and whether I can do something for you as a Professional Mistress. I receive messages every day with just “Hi” or “Hi There” is very little we can do with that. 
Respect is the basis too here. 

4:
keep communicating!

Perhaps the most important; keep communicating with your Mistress. By continuing to communicate, your mistress will learn to recognize and understand your do's and don'ts.
This can be done during the session (if your Mistress gives you permission to talk) by honestly answering your Mistress's questions or in before and after session conversations.