Everyone who begins the consensual slavery path starts as a blank slate. At some point, you learn enough to want to do this. This is true whether you want to be an owner or a slave. Exactly how this happens for each person is not something that can be dealt with here. There are too many variables and differences among people. What this can do is help you progress from nothing to something.
Most people find out about the real possibilities of consensual slavery through several sources. The most common ways are books, from the Gor Chronicles to Harlequin romances, movies, reading history, BDSM or other porn, internet searches, websites, or online sites such as SecondLife, someone you meet or know who is involved, or someone who wants to own you or to be owned by you. Any list that can be made can never include everything possible. Everyone has their own reasons for doing this and their own path to their starting point. Even that starting point will be different for different people.
Now you are at the point where you want to begin. How do you do it? How do you learn what you need to learn to train a slave or learn to be a consensual slave? Many will say that the slave doesn't need to know anything; they only need to obey and learn what their trainer or owner wants to teach them. While it can work that way, it is better if the potential slave also knows what is happening at least to some extent, and more importantly, why it is happening. That way, she can work with and not against the enslavement.
The owner or trainer, on the other hand, really does need to know as much as they can, and the more experience they have, the better. How does someone gain that experience when they are starting from scratch? Read, research, watch, and talk to others, find a mentor, find someone to work or practice with, and of course, the ever-popular, get a slave and then figure out what to do. Regretfully, the last is what most do. It also produces the worst results in most cases.
You are obviously reading and researching, otherwise you wouldn't be reading this. As I stated in the beginning, the information here is not sufficient by itself to train a slave, but it will give you a start and a better one than many have had. The best way to get experience is to have someone, or better, several people, who are experienced mentor you learning to teach you and own a slave. They can give you both practical and theoretical knowledge, and sometimes someone to work with as a slave. In some of the Leather traditions, a person spends time first as a slave before they are allowed to own another. In others, such as Gorean or Odalisque traditions, this rarely happens. In general, non-traditional BDSM consensual slavery, anything can happen as far as how to learn. Whether you should serve before you own or not, it is totally freeform and up to the people involved. This is also where much that is called slavery isn't really consensual slavery, but D/s with titles. These relationships tend to last less than many of the other ones that come from some tradition. I believe the reason for that is that everything is made up for each person, and there is nothing beyond the specific relationship to draw from. That is my opinion; I don't have any other than anecdotal evidence to support this.
You can read and research. Several books are available on BDSM techniques, slavery, and how people do or have done it. There are even a few on specialty subjects within the consensual enslavement/slavery envelope. Many of them are available on Amazon. Others are available directly from the authors or other book and eBook outlets. You will find that many of them are books about how the author does things or had things done to them. What most seem to lack is why things are done and what the internal mechanisms are. I am trying to change that.
The more you read, the more you learn, and the more tools you have at your disposal. However, you will also read a lot of things that may not work for you or don't apply to you, and what you want to do. You will also find general tips on how others do things that are worth looking into in case you find a need or use for them later. One book I read has a large section on formal dining, place settings, and serving. If you don't do formal dinners, or have never done one, it is interesting reading, and you may find it useful someday, even though it is not something you will teach a slave or require them to learn.
The more reading and research you do, the more you will find conflicting messages and techniques. You will also find very similar ones. Which ones are right? Which ones are wrong? The answer is, anything could be either for you. In the end, only the person doing the training can decide what they will use, either from sources or tools.
What sources do you use? There are many possibilities. There are books about consensual enslavement. There are websites about it, from serious training sites to the much more common porn sites. The best of which is by kink.com. Of their sites, I can only recommend two for study. "The Training of O” and “The Upper Room” sites have some useful techniques, but you do have to remember that in the first and many in the second, everyone involved are paid performer and they reshoot scenes that don't work right the first time.
The only exceptions to the reshooting are the videos that are shot as one scene or obviously in one session. Remember that kink.com’s emphasis is training sex and pain slaves and uses many humiliation techniques in doing so. Portions of what they do, such as some of kink's training techniques for the Upper Room, do have usage in consensual enslavement when you leave out most of the pain and humiliation, and some of the sexual ones as well. The rest can be useful, and you will see some of them in other sources.
There also exist websites that will sell you complete slave training manuals. I have never looked at what they offer because I did not assume they would be worth the money. Maybe someday I will spend the money on it, but I doubt it. There are also training seminars, both paid and at BDSM events, where you can learn about consensual enslavement, consensual slavery, and training. From the class information I have seen, most will teach you BDSM techniques, some consensual enslavement ones, and they will be talking about how someone else does it, not why something works.
You do not gain direct experience by reading and researching. What you gain is the knowledge to make fewer mistakes, to learn faster, and to do better when you do this with someone else.
Previously, I mentioned having someone mentor or teach you as a way to gain experience. This works very well if you can observe how they do things in practice or if they have someone you can work with in situations of more and more control. This shades into finding someone you can effectively practice with before you own. This is done quite often in BDSM classes where they are teaching techniques with their toys and various play activities.
For the sake of a clear example, I will use one of the more common BDSM toys, a flogger, and then show how practice with it relates to consensual slavery practice. Many people buy a flogger, then immediately want to use it on someone.
It does help if someone shows you how to use it first, how hard to hit, and how to control the strike and the force of the blows. Many people have recommended hitting pillows or chair backs for a while to practice throwing the blow and controlling the force before you ever use it on another person. Speaking as someone who spent decades in a sword based martial art thawing very similar blows, practicing before you hit someone is a very good thing.
The other option is if you have someone who will let you use their toys and practice on their sub to learn how to use the flogger. That is how I was first introduced to using one. It is not the best way to use a flogger, but it is an example of ways you would learn how to manage a slave and eventually train one by being even a small part of a slave's training.
So, how do you become a part of another slave's training so you can learn to train your own slave?