User interface for web applications in general contain various buttons for performing CRUD operations. What would be the suggested naming convention for button labels while performing the following actions..

• User creation (Add User... or Add User or Add user)
• Event creation (Add Event... or Add Event or Add event)
• View users button (List All Users or List All users or List all users )

Most of the sites seem to contain the last option (e.g. Add user) where the first alphabet in the word is capitalized and rest all are lower case). What would be a better practice here?