My shed is under the house not very big. 
The first thing I did was to paint the underside of the floorboards white to reflect light. 
Originally I had secondhand 4’ twin flouros but they are all gone now.  I have a mixture of LED light panels, battens and downlights all as plugins on surface sockets. I’ve recently added extra LED lights as with age the eyes need the extra lighting. 

Life’s Good, Enjoy Each New Day’s Blessings