As far as class/race starter combos go…
Orc/Warlord is incredibly straightforward. Orcs are the least tricksy of races, but real good at hitting things and taking a punch. This combo sucks at ranged and excels at melee. Just run your big beefy dudes at the enemy, and if you can avoid whatever their tricksy nonsense is, you’ll win handily.
Elf/Warlord is similarly straightforward. More ranged, less melee/beef, but still about smashing the other guy in the mouth.
Goblin/Theocrat is a personal favorite. Gobs are relatively weak but numerous, and Theocrat plays to the “numerous” strength while mitigating the “weak” drawback (mostly because Crusaders are the beefiest beef that ever beefed, even Goblin Crusaders, and they’re a cheap and readily available T2). Theocrat ain’t that tricksy, but it plays more to a “boom/turtle” style than a “rush” style.
Rogue is probably the tricksiest base class. Any Rogue leader has to rely on abusing mismatches between his/her goofy units and abilities; you can’t just run a bunch of dudes at the enemy and hope to win (Shadow Elementals notwithstanding. Oh, did I mention that their weak Brigand T1s can evolve into Shadow Elementals? Because that’s awesome.)
Dreadnought is moderately tricksy. You get some mightily abusive units (Flame Tanks, Cannon) that have significant drawbacks. If you can work around them, you can do some silly things, but machine-type units are a pain in that they don’t naturally regen so you have to keep Engineers or appropriately specced heroes around.
Neither Sorcerer nor Druid is all that tricksy, like @Scotch_Lufkin said. You just summon your big stompies instead of building them like a Warlord or a Theocrat (or a Rogue) does. As you would imagine, there are some fun spells to sling in there.
None of the base races are terribly tricksy. Dwarves and Orcs are the most straightforward, Humans and Dwarves are nice in that they get support units that can heal so you don’t have to rely on heroes to provide healing, Elves shoot the bejeezus out of everything and are poncy, Goblins also shoot the bejeezus out of everything but are green and numerous, and uh whatever races I’m forgetting do other things.
I wouldn’t recommend any of the expansion races/classes (halfling, tigran, frostling, necromancer) until you get a feel for the rules, unless diving into the deep end is your thing, in which case have fun! They are all tricksy.