Actually I used to have an outfit loaded with sequins, a playing card pip theme and shimmering cape (think Elvis) that actually lit up... granted, it was the 70s and disco was huge and glitz expected (did I mention the 4" stacked shoes?)
Costume depends on the who and what you plan on being. Pop Hyden has become your classic confidence man vs. the clean cut comic he was a few short decades ago (when we were but kids). Billy McComb exploited his UKness in his latter years as have many others you all exported our way, because it works here... but according to a couple of my chums on that side of the pond, it works over there as well -- Brits love to laugh at themselves while American's think they are only supposed to laugh at everyone but themselves
So the question you need to ask is WHO AM I?
Knowing the kind of magic you prefer to do most will help; it helps on many levels because you will become more focused and thus, more specialized in what it is you will allow yourself to do that defines that image or character; everything from the type of effects you perform and any special requirements they may have when it comes to costuming, to the type of venues and income you see yourself fitting. The old saying being to
dress a pay grade higher than your audience whenever possible and at minimum, their equal... that is, if you aren't heading towards a specific costume for a specific reason.
The other rule of thumb for people just starting out; model your look off of the people you look up to the most that are of the level of success you want to be at in the next 3-5 years. By learning to mimic the look and essence of such people (and I'm not saying to do an "impersonation" mind you), the more you will psychologically start connecting with the energy that allowed them to prosper. That's why military and business leaders study the books and records of others that were successful in their field -- it's a model!
So think it out and simply start carving out your niche.
