I want to give you shortcuts because i don't want you to drop the game just because you don't know which key to use to raise undead or how to move.

Well, first of all, when in doubt press the "?" key ("shift+*"), it will bring up the hotkey commands for any screen that you are on. [Thanks to Outis]

Do not forget to tick "Battle reports" option when you are creating a new game, it will give you a chance to quickly see what happened in battles.

By right clicking you may see descriptions in general (i mean on world map or on battle map or even on descriptions itself. just right click on things u want info).

You can select a commander by right clicking on world map, or with "n" key you may select your next commander.

by left clicking world map squares you may set destination for your commander on world map, and by clicking the square again (provided your commander has enough movement points left) you may move your commander.

With "s" key (on world map) you may sleep/station your commander so when you try to end turn, game won't bother you about him until you activate him by selecting him.

With space key you may pass commander's turn for just one turn so game won't bother you by showing you that commander when you press "n" to see the next commander on that one single turn.

you may chain or break commanders to/from each other by selecting them on the top left list while holding shift.

With "r" key you may recruit troops or commanders, or buy items.

When you press "r" to recruit you deploy at your capital as default, you have to pick from the list of citadels to recruit at a specific citadel, it's annoying, because of that in order to recruit in a specific citadel quickly you may hold right click on the specific citadel (on world map ofc).

When in the citadel recruitment menu, press CTRL + left click on basic unit to recruit that unit every turn. A green dot signifies it's active.
Very helpful once your kingdom gets to a certain size. [Thanks to Korriban for this one]

Rituals/unique faction powers are used with "p" key, you can also see it on the little top right corner menu when you select your Baron or Necromancer or whatever (on world map).

With "y" key you may end your turn.

With "L" key you may open trade options.

With "t" key you may assign soldiers to your commanders. (important since you don't want to attack or move without your units)

In assignment mode with "a" key you may select (assign) all units.

you can double left click on a type of unit to pick all of that type of unit.

you may press "s" to select or deselect slow units like catapults or heavy infantry which are making your commander move slower on world map.

"f" will select all fast units (units with 4 ap). [Thanks to reddragonfall]

"+" and "-" adds or removes 10 units from the last selected type. [Thanks to Mayheim]

hold shift to select a row or a square or whatever.

When you view a battle happening you can use "s" key to speed it up or "q" to immediately quit the report so you don't have to wait or annoy yourself by clicking things with your mouse.

"space" will pause them and "n" will set them to normal speed. [thanks to reddragonfall]