If you are asking how to remember the pin assignments I can't imagine why would you want to learn them from memory, this is why the datasheet exists.
If you want you can print a page with just the pinout so you can access it more easily.
---------- Post added at 21:17 ---------- Previous post was at 21:15 ----------
P.S in ARMwizard there is a button "show MCU" that can show the pinout of the selected mcu (not available to 100 pin models)