First, forget about performing right now. You first have to develop a routine, as well as a character.
First, what you want to do is ask yourself, "Who am I?" This is quite important, so you can determine what type of performer you are, as well as develop a character. You need to know this before you can even begin thinking about performing on stage.
Next, you need to create a wonderful routine. You do this by examining what type of performer you are, what type of magic interests you, your character, and what you actually want to achieve.
You need to find magic effects that fit your style, and that you can build a great presentation to. Don't try to just slop something together, because it won't work. Now, it's really important to decide if you want to be more of a comedian magician, a sleight of hand/manipulation magician, a large illusion magician, etc. Once you decide, it's easier to find effects. But that's something you must do yourself. I suggest watching videos of other stage magicians, and pick and choose what you like.
Once you have gotten that part done, you can move on to getting booked. There are various ways of doing this as well. One, you can rent a theater yourself, and produce your own show. It takes a considerable amount of money off hand, but you gain in back in the long run; that is if you promote the show correctly, and do a good job.
Another way is to find an agent who deals with booking stage shows. Some people don't care for getting agents or managers. Personally, I will deal with an agent, if it's a must (for instance, getting into some comedy clubs). Otherwise, I would rather do it all on my own. It's a choice you have to make.
The last way I will mention is to start calling places that do stage shows. These can include churches, dinner theaters, schools, colleges, hotels, and casinos. That's not a complete list, but just a starter. But be aware that you really have to sell yourself. And you will be getting a lot of rejections. That's just how it goes. It's going to take you a lot of hard work, and a lot of time.