nice job

depends what sort of shade you want, a simple one is just add a cylinder an scale one edge bigger gives that cone shape(dont forget to untick cap ends!! I often do)

or if u want a dome type add a sphere cut off the bottom then extrude/scale the bottom edge with propotional editing on (mouse wheel controls its strength) delete centre top vertex for a hole in top

 

ps in object mode click the smooth button in left hand tool bar, wont affect the poly count but will make viewers go arrrrhh

have fun