Your references are just past choices wearing name tags.

People who vouch for you are not evaluating your potential; they are reporting what you did while they were watching. That report was written gradually, in ordinary weeks, long before anyone thought of asking for it. Which means the work of getting a good reference happens years before the request.

Treat your current situation as the material for a future account of you. Be someone specific and useful in it, and stay in light contact with the people who saw it.