We love toolbars. About 90% of our commands are launched from single-click toolbar buttons. We use no flyouts and our toolbars change as needed. We firmly believe in the 80-20 rule, that is, you use 20% of the commands 80% of the time. 

The first step is to make a copy of your original 'Acad.mns' file so you won't irretrievably lose anything. 
You can either modify existing toolbars, or create new ones. Part 2 will cover creating new toolbars.
The next step is to be aware of the command buttons you use the most, the buttons you use occasionally, and the buttons you never use.
The buttons you never use should simply be removed from their toolbars.To remove a button from a toolbar, follow these steps.

First, right-click on any toolbar on your screen:


Now, select 'Customize':


This will bring up the 'Toolbars' dialog. Now click on 'Customize...':


This will bring up the Customize Toolbars' dialog:


Now, all you need to do is click on and drag the button you want to remove and drop it onto the drawing area:




And the button is gone:


You follow this method to clean out all unused toolbar buttons as the first step of customization.

In Part 2, we look at creating new toolbars.
In Part 3, we look at creating custom toolbar buttons.