You can not change your physical appearance with a spell. You can transform your life by choosing different methods of living. Meditation is a good way to start, eating right, and making heathly choices. If you live your life in misery (always looking to whats wrong) instead of looking at things in a positive manner, nothing will change.
It is absolutely possibly to change your life with magic. It is not so likely to do so with a single spell; magic is a process.
Beginning a practice is a change in your life, even if it is just one of the details. But let's look a little closer:
Meditation changes the brain. It has positive benefits, and some types of meditation have very specific effects. People who meditate regularly have better mood control, better concentration, and more. Since meditation is the first place a lot of people are recommended to start, it will immediately put you on a path to change your life with magic. In fact, there are a lot of people who begin and end with meditation.
As for further practice, some traditions and individuals choose to only focus on internal change; personal development. There are some less and more complicated methods to explore one's personality for the sake of reducing and hopefully ridding negative aspects of one's personality. Some traditions call this shadow work, while some people insist that the Solomonic tradition is about facing one's own demons more than it is about calling upon external entities. The road to internal development can be very complicated, depending on which method a person chooses.
As for external change, opinions of certain traditions may discourage it. But many people have success, attracting better pay or a more satisfying job, seeking a more ideal partner, having favor in people's eyes, general success in an endeavor, and more.
So yes: There is every potential to change your life with magic.
As for changing your appearance, that is not so doable. Exercise, eating habits, stress levels, time spent outdoors, and more can affect appearance. But a lot of aspects are genetic, and thus cannot be changed with magic. However, learning confidence and self-acceptance can be part of a magic practice, and these things go a very long way in how others perceive you.
