To be effective, user personas cannot be products of your imagination or guesswork.
They must be representations of your actual best customers. That is why user persona creation must be backed up with data and input from your target audience.
How to create a user persona may sound like a daunting question, but the process is anything but complicated. A short survey is a perfect way to kick-start your user research.
Not only will it validate your initial assumptions about the personas, but it'll also provide you with quantitative (and qualitative) data. It'll make it easy for you to arrange user interviews to deepen your understanding and obtain more insights into the customers/users.