To organize your Inbox, use a similar concept as paper.
First ask yourself: Do I really need to keep this email, or can I throw it away/delete it?
Next ask yourself: Does it require action or am I keeping it only for historical/future reference? If keeping only for future reference, immediately move/file the email into a sub-folder (Customers > Customer A, Propects > Prospect A, Vendors > Vendor A).
If email requires action, should you delegate; if so, delegate immediately and delete/or file email to a sub-folder.
The only remaining items will be emails that require action by yourself. Now roll-up your sleeves and apply some elbow grease! Once action is complete, delete or file email into a sub-folder.