How to fix my flying squirrel model...?

I made a flying squirrel model with cardboard. how do I give it more lift?How to fix my flying squirrel model...?
Lift is a function of bird and airplane wings. I don't think, even in life, a flying squirrel can actually rise in elevation during it's gliding, non-powered flight.





To provide lift, you would have to devise more of a 3D model, and mimic the shape of an airplane wing (in cross section).How to fix my flying squirrel model...?
How are we suppose to know this? If you can provide a diagram, or picture or something we can examine we might be able to offer suggestions. As it is....we have virtually nothing to go on.