Get halfway through a model and find it's an unworkable mess? Can't add edge loops where you need them? Can't subdivide a mesh properly? If any of this sounds familiar check this course out.
If you are interested in being better than just "good" in your knowledge of MAYA, you certainly should learn MEL . . .
Why?
Suppose for example you want to do something like set up a default lighting system, so that whenever you create a scene, you can create the default lighting system without having to repeat it every time . . .
It is easier that you might suppose . . . on the lower right, you can click on the script editor. Click on "Edit>Clear History" if there is any history listed, then minimize or move the script editor to one side and create the lights as you would like them to be for the generic lighting system that you want to use.
After you have finished the "generic lighting system", re-open the script editor and highlight the code that was generated in the history window, and put your cursor over it and hold down the right mouse button and drag it to the shelf. A new shelf function will be created and then whenever you create a new scene, you can add the lighting to it by simply pressing that shelf icon. Now that was a lot of hard work coding that wasn't it? :attn:
You can even create your own customized shelf icon in photoshop to use for whatever functions you create by going to "window>setting/preferences>shelves", select "change image" and select the icon you created.
It is good to create a generic icon, that way you can use it as a template, whenever you want to create a new icon. There is a set number of pixels it has to be, I do not recall what it is, but I am including the "default lighting" icon I created.
You can use the script editor as a means of creating all kinds of functions that will allow you to save yourself a lot of time and learn more about MEL . . .