It\'s common for me to press alt-f10 (in GNU/Linux) after Emacs start up for maximizing window (in the Emacs terminology, it\'s actually a frame). Most of the time I press t
Putting this into my ~/.emacs works for me (Emacs 24.5.1 on Debian GNU/Linux):
(toggle-frame-maximized)
To find that, I checked the name of the command called by the M-F10 shortcut with: C-h M-F10: it returned "toggle-frame-maximized", which I just call in my ~/.emacs.
Another solution, probably even better, found here:
(add-to-list 'initial-frame-alist '(fullscreen . maximized))