I have several clients that have a meditation practice. I am asked a lot what is the similarity and the difference between the two. From doing both on a personal level I can tell you what I have discovered.
In meditation there may not be an objective other than the obvious joy or peace of mind that you experience while meditating. In self hypnosis there is usually a goal of some kind that is the object of a desire to change something or to experience something.
Meditation can be a personal journey with no expectations attached. And it's really beyond my ability to try to explain it in words but the similarity to hypnosis is the ability to go within. If you think about it you're either looking out and experiencing or you go inside to experience.
When you decide to go inside by whatever means the process is very similar. People that have meditated for awhile can usually zero in on their desired "place". People that have used self-hypnosis can zero in on their desired place.
In the early days it may not be that easy because the conscious mind doesn't always want to give over the reins, it wants to analyze. Like anything else the more you practice, you find what works for you. There might be a particular technique or process that will work most of the time. Once you discover it and practice it, you zero in and have your experience.
One thing I have found is hypnosis can help people to meditate by enabling someone to achieve their desired state quicker. To turn off the conscious, "monkey mind" as the Buddhists say.
It can be very beneficial to beginning a meditator to learn self-hypnosis.