I use the GeForce Experience (GFE) utility to update my GPU drivers. Some people like it, others do not. I like it because it's simple, you have the option to do a clean install (wipes the previous drivers out first as always recommended when updating drivers manually), and it gives out all the drivers available to upgrade when selecting the custom install option (HD audio drivers PhysX driver, 3D driver, etc.).
Otherwise manually is always the best way to go.