I been in the 600’s for a long time and recently found that I can report my rental history and payments.
Its not a free service but has saved me thousands because of my car loan and mortgage.
How it works is they will contact your landlord and verify how much you paid for rent and how long you lived there.
They then will add a trade line on your credit report with all the history.
My score jumped to the 700’s and i feel great.
RentReporters is the service I used it was easy and there is a coupon for $ 20 off right now using code TMUK now sure when it will expire.