Spin coat of Graphene oxide on glass slides
The procedure will vary with the size and shape of the glass, the concentration and viscosity of your graphene oxide dispersion, the solvent you're using, the wettability of your glass slide, and so on. You'll need to figure out the parameters yourself by varying the spinning conditions, measuring the resulting film thicknesses via profilometry/AFM/cross-sectional SEM, and then constructing spin curves (examples).