The layout of the menu bar is the same as the overall interface; frequently used commands are placed on the left. Because Maya has many menus for various tasks, the menu bar has been split into a fixed part (File, Edit, Create, Select, Modify, Display, Windows,[...] ,Cache, Help) and a part that can be set to a specific task using a. This pull-down is located on the left side, directly beneath the File and Edit menus:
When you change the pull-down menu from Modeling to Animation, the menus after 'Windows' are changed to the menus specific for animation:
And below when set back to Modeling:
Let's take a closer look at the 'Modeling' set menu bar. It starts with four items for polygonal mesh objects: Mesh, Edit Mesh, Mesh Tools, Mesh Display. Mesh contains commands for changing polygon objects. The next two menus are Edit Mesh and Mesh tools: functions to add/remove polygon objects and/or components to polygone meshes. Mesh Display contains helpful display functions for polygonal objects/components.
Menus Curves and Surfaces contain commands related to NURBS curves and surfaces.
It's impossible to know every command by heart. But when you see the logic of the way all commands are structured in the menus, it shouldn't take too long to find what you're looking for.