Hey ummm, for starting nation choice I would really suggest T'ien Chi, either Early or Mid (they lose something in Late
). Both nations get incredible magic diversity in their national mages, and both get excellent national troops with solid PD.
They are not a nation that you can so easily get a real "handle" on, but they have some of the best cheap troops to deal with the AI stepping up the fight, as well as huge magical diversity so that you can really explore different spells and different tactics within one game.
Using Fast research is one way to get into the more "exciting" parts of the game, I would also suggest boosting Magic Sites to at least 70. A large gem income will give you the chance to empower your pretender in all paths, and try out all of the summons and global spells that you are curious about.
Also bear in mind, the interactions of the stats are far less "spreadsheet-like" than you might imagine. First, paying close attention to the combat mechanics in the manual will show you how things like Shield Parry, Repel, multiple attack Defense reduction, encumbrance, and so many other factors start to open up so many potential interactions even just with the basic troops. But it's when magic becomes more prevalent, and you start adding in interesting buffs and summons (and a little fire and brimstone, too) that the battles really start to come alive.
Ultimately, what makes Dom3 sparkle is not so much the gameplay itself, as it is the content. And there is so much cool and interesting content, it's nearly impossible to become deeply familiar with all of it (very few succeed in that quest, most dehydrate first).
Also if you think the action is just a tad too slow - try a game where you take a pretender who has Fear +? and give a starting Dominion of 10. Don't bother boosting his magic, and keep him awake. On the first turn, attack blindly, and laugh as he massacres the independents. Continue fiddling with that game until he dies or gets a horrible affliction. Now go back, do it again but pay attention to the magic, make sure he has 1 Astral (Ethereal and Luck), or 2 Nature (Regen), or 2 Water (Quickness) or something that gives some solid buffing that doesn't take forever to research (like Soul Vortex is neat, but you won't get it in the first year), and then go straight for those buffs, and see how long he lasts. Almost everyone has immense fun with supremely powerful critters, it's just too hilarious to watch them eat things.
It's by no means the only path to victory, but it's a fun way to open up your eyes to the vast potential that the game has to offer.