Start with Under/Over which is a free e-book from Vanishing, Inc. written by Joshua Jay. It is directed at younger magicians and their parents, but would be helpful to you.
Rick's advice is really good.
If you are doing the "walk-up" performance, start off with just talking to the people. Actually, just practice talking to people without doing magic. Talk to people in the line at the store. Talk to people while waiting in line anywhere. Open doors for people and when they say thank you, tell them to have a nice day. Say good morning to people.
A great book is Leil Lowndes'
How to Talk to Anyone. It is not magic related, but is a good book for real life.
As Rick said, it is excitement and being nervous. Essentially, your body feels it is in a situation where you need to fight or flee. It is really a primal survival instinct which allows you to react quickly when you meet new people just in case they decide to kill you and eat you. What you are feeling is truly nervous energy. If you embrace this energy, it can actually help you in performing because your mental and physical reflexes are primed. To alleviate the shaking, you need feedback from the audience. If I'm right, the shaking usually subsides after you finish the first effect? That is because they like the effect and like you. As a result, your body decided that the spectators actually are not going to kill you and eat you. The way to get rid of the shakes sooner, is to engage the audience. If you talk to the spectators first, your body relaxes. If you say you are working on new effects, your body relaxes because if you screw up, it is ok. If you have a set opening presentation, that helps because you go into your script and that distracts your body from its fear of being eaten because you are focusing on something familiar and safe. As you become more experienced, your body still will get the energy surge, but it will control it because you've done this before and weren't eaten.
For me, I have a set opening for my show that is developed to draw the audience into the show and that gets a reaction in the second line:
When I tell people that I’m really interested in magic and that I’m a magician, everyone always asks me how I became so interested in magic. I think that the question they really want to ask is “why would an grown adult be so interested in magic?” Regardless of the question, the answer is the same. It’s my Uncle Jim’s fault.
It makes a connection with the audience, and I can go on with the routine because I know they don't want to kill and eat me. As you do this for a while, you will also find that being introduced as "the magician" or introducing yourself as the magician gives you an elevated status -- you must be good because you are "hired" (whether you are being paid or not) as the entertainment.
It all depends on your audience. For kids your age, what you are wearing works. If you are performing for 40-Something adults, move it up a notch. Maybe a Polo Shirt and Khakis or black jeans.
Start by developing a show. Decide what type of show you want to do. Is it close up, walk around, parlor, stage magic or mentalism? Decide who your audience is. Adults, kids, hospital patients, nursing home residents, etc. Build the elements of the show -- your character, your effects and your presentation. I'd be glad to help you with the design of the show. Once you have the show, there will be lots of opportunites to perform it. I agree that you should start doing charity shows to get experience and get your name out there. Don't do "free" shows for people and groups other than charities.
A great book on performance is Ken Webber's Maximum Entertainment. It is amazingly practically and has a lot of useful advice.
Summer camp is a great place to perform formally and informally. I'm actually working with my 14 year old son on routines to perform as a counselor at camp as one-off performances. If there is an opportunity, do a show at camp for all the kids attending the show.
Under Over has half the book written for parents. Let me add a couple of thoughts to that (feel free to share with your parents):
Magic has many facets. On its face, magic is a performing art. But it is different than most performing arts because to develop an act, the magician has to be the writer, technical consultant, director and performer. Shows are not a series of tricks performed in sequence, but a script where the words said need to not only align with the effects but enhance the effects. There are very few effects that can be performed "out-of-the-box" -- most effects require personal touches. Some effects requiring finding or building the props. More importantly, all effects need to be learned, practiced and rehearsed. A show is not something that you write, practice and perform. It is more like, write, revise, practice, revise, rehearse, revise, perform and revise. Performing requires a stage presence as well as acting and public speaking abilities. At every stage, you are developing life skills that will help you outside of magic.
As you get deeper into magic, you likely will start accumulating books and knowledge. You will start to understand the history and variations of effects. You will learn how true it is that "everything is in Tarbell" or Modern Magic or Greater Magic. Your present lists will sound like you are trying to acquire a library... and maybe you are. This leads to reading, an understanding of the history of magic, research, critical thinking and development of new ideas and application of old ideas.
Working at the magic shop will develop people skills as well as sleight of hand and performance skills. Nothing like doing the same effect over and over.
Magic might not result in you earning a fortune in money... you might only end up with a wealth of knowldge and skills.
