Classic lashing is the technique of applying one lash extension to one natural lash. Classic sets add just a little 'oomph' to your natural lashes and are great for first-timers as this set will look like you just have really good mascara on.
Silk refers to the way the lashes are cut. Silk lashes tend to have a glossier appearance and are tapered at the ends leaving a thicker lash base. This provides for a darker lash line.
Looking for a more dense, dramatic look? Try Hybrid or Volume.