Saikii
Go to a convention.
Buy an official cosplay outfit.
They're a lot of fun. My first one was a small local anime convention, which was a nice way to get familiar with the convention lifestyle but still be close to home. Then I "leveled up" by attending Emerald City Comicon with my friend. I've been to the anime convention for two years now and will be going to ECCC for the second year in the row next March with my friend again. I have a few other conventions I have in mind that I might attend in the future.
If you plan on buying your cosplay outfits from someone, rather than making them yourself, just make sure to research the people you are interested in buying stuff from and reading the reviews given of their products (if any are available). There's are some folks out there who are awesome costume commissioners (like JoEllen Elam of
Firefly Path [I got my magenta unicorn horn circlet ((this is the
gold version)) and
rose tea time necklace from her]) and there are some who produce poor quality versions. Always good to know that you will be getting your money's worth.