Sometimes you get an idea for an OC without really having a clear picture of it. That's fine! Sometimes, having a concept can help you have a clearer vision for it, though sometimes, if it's vague, it can be a hindrance.

Try to narrow down a personality and/or a species from your idea before tackling the design. Making Pinterest boards for your OC concept can really help you get a feel for the personality, aesthetic, and design of your concept.