How to Choose a Stage Name
Whether you want to be a professional singer or professional actor, you will want a good stage name. If you were born with one, more power to you; but if you're among those who were born with a name that's to difficult to pronounce, or one that's too easy to forget, you'll want to spiff it up a bit. Note that this is different from choosing a pen name (and I say this as someone who has both) and you've got more leeway with a stage name than you would with a pen name because singers and actors can get away with more and don't need to be taken seriously to be respected for their talent. But there are things which should still be considered when choosing a stage name and the following list should be taken into account before selecting one.
Make sure people can say it.
This is way, way more important for a stage name than for a pen name because you're going to hear it way more often. If you're a writer, people will be reading your name often, but you won't hear it on a daily basis unless you're uber famous. If you're a singer or an actor, however, you'll be hearing it every time you perform professionally, whether by an emcee or people asking you for autographs. You don't want a name that no one can pronounce, as this will really get on your nerves after awhile.
Make sure it's not silly.
Unless your genre is bizarre or comedic, you'll probably want a name that isn't too silly. Let me give you an example: Romeo Blue was Lenny Kravitz's name before he wised up and went with what his parents gave him. Note that he wasn't even remotely famous as Romeo Blue and this is probably the first time you've heard of it! There is such a thing as trying too hard.
Make sure you take modern slang into account.
With names like J.Lo, LiLo and SuBo being common shortenings of perfectly normal names, you'll want to take care with your stage name and try to anticipate what people might start calling you if you get famous. For example, if you call yourself Leslie Bohemian, you may not enjoy it if the media shortens that up in an attempt to be witty. So think about these things before you choose your stage name.
Don't get clever with the spelling.
If your name is Michelle and you start spelling it Mitchelle with a silent T (I know someone who did this!) then don't be surprised when everyone starts thinking your name is Mitchelle with an audible T and calls you something that sounds like it! Your name isn't supposed to be more clever than you are.
Don't name yourself after anyone famous.
Do not start calling yourself Jane Joplin just because you think you sound like Janis -- unless your job is that of an impersonator. If you want to be taken seriously as a performer and be known for your own talent, use your own name, or a stage name that is singular unto you. If you adopt the surname or first name of someone famous, people will tend to roll their eyes at you. Get known on your own, for you own talent.