Command line parameters - Start the game with one of the following command line parameters to activate the corresponding function:

Windowed mode -win
Set horizontal video size -xres <number>
Set vertical video size -yres <number>

Easy wins with Angmar faction - When fighting under the Angmar faction, build a few Mills. Then, build a Hall Of The Kings Men, and train two to four Dark Rangers. Build the Armory and upgrade it to level 2. Then, research the Ice Arrows for an extra boost in damage.

The rangers will kill your enemies very quickly; however, beware of Cavalry units. Train some Thrall Masters with the Spearmen and use them to defend the rangers until you can build up a large enough army and defeat your enemy.