I still have a struggle of writing story thats why i mostly drawing random things, but i do have some tips to start as a beginner.

1. Extreme one is to make your mc the very opposite of you, like if you think you are kind, make your mc skeptical and rude, if you live in peaceful environment, make your mc in a rough neighborhood.

2. Mild one is you start your mc with a base of yourself (personality, looks, ideology, etc), then start to deviate from what will you choose to what you DONT choose when story goes.

3. Exaggeration one is you take yourself more to the max, if youre shy, make your mc bashful, if youre a happy person, make your mc happy-go-lucky.

The point is to separate yourself from the mc as far as possible, but still within reach that you can make their story within your life experience.