User Role Editor WordPress plugin allows you to change standard WordPress user roles capabilities with easiness of a few mouse clicks. Just turn on check boxes of capabilities you wish to add to the selected role and click “Update” button to save your changes. That’s done. In case you made some unneccessary change you always have the “Reset” button to restore roles state from the automatically made backup copy. Add and tune your own custom roles whiche you can assign to the users then. Delete self-made roles. Change defaul user role.
Why it could be necessary? Let’s suppose you wish that your multi-authored blog contributors upload their own graphics to use in their posts. WordPress “contributor” role has no such capability by default. In such situation you have needed to change user role capabilities manually using SQL client as I described at “How to change wordpress user role capabilities” post, if you have enough knowledge in that field. But what to do if you have not?