This is the way.Here’s just a couple of simple suggestions. Get rig of everything in the basement. Make it spotless. Hire someone to apply epoxy paint to the floor. ( I assume it’s plain concrete). That will boost the wow factor a lot.
One man's treasure is another man's T-R-A-S-H, no matter what the value of the items.
Get every single thing out of that basement.
There is a very small number of buyers that want to move into a house with somebody else's stuff in it, as is evidenced by the fact that it's been on the market for 13 years.