Just purchased Dominions 3...

[Morkilus]

Ulm's my favorite newbie nation since their low magic diversity (at least in the first two eras) focuses you on what to research, and a critical mass of heavy armor units is effective enough against indies. Their diversity of unit weaponry lets you learn the combat system and proper tactical placement (cavalry for flanking mages, high-prot + shields against arrows, flails vs chaff infantry). I'd say Niefelheim is a good step after that to learn how to use sacred units and build thugs, which are commanders that can take poorly defended provinces on their own.

[Gandalf Parker]

Yeah I like to recommend Ulm and nations like it for beginners. Most people coming into the game tend to understand what to do with mounted knights, guys with shields and swords, archers. It lets them get used to the game mechanics before getting into the new-concept stuff.

[MaxWilson]

Similarly to playing around with Ulm, you might try playing around with the easy spell mod (Save this to c:\Program Files\Dominions3\mods directory or equivalent, and go to Preferences/Mods to turn on "All spells pre-researched"). Then you can select a nation like, say, EA C'tis and see how much you like their spellcasters. Realizing of course that in a real game you won't have access to all those spells from the start of the game, it might still be fun to see what magic schools you want most.

-Max

[Nick_K]

If you've played the demo, then I imagine you already know the basics, so just jump in and enjoy.

If not, I'd recommend trying someone like MA Ulm, MA or LA Man or Pythium, although this is hardly an exhaustive list. I'd recommend avoiding blood nations and anything with weird special rules like Mictlan or LA Ermor. Set the AIs to easy if you want to win as Dominions is quite hard until you know the game well. Specify which nations oppose you - avoid facing LA Ermor or any water nation for your first game as they require somewhat more specific strategies to deal with.

As for nation setup, I'd recommend just going with how you envisage the pretender rather than worrying about getting a perfect build. Good scales are probably simpler to gain advantage from than high magic, although some magic is always useful. Make sure your starting dominion is at least 5... otherwise, whatever you like.

My number one tip for actual singleplayer play is to buy mercenaries. Bid very slightly over their asking price to win the auction. They give a huge boost to early expansion. Also, understand that your pretender may well die. Don't get too upset if you have to call him back and he loses some of his magic. You can always even the scales by killing the AIs' pretenders!