Rezca: Assuming you can get to the resources fast enough ^_^
I just started a game and there was a Redwood right next to me. In the previous shard half the game was over before I got some Redwood, but I got Iron and Horses almost immediately.
The shard before that was a total faliure because of some financial mistakes I made, but I had two redwood, horses, and Iron within one tile of me, and while exploring came across (Dironum?) but never conquered the guards before I gave the shard up to my enemies.
So scouting out and quickly grabbing the tactical resources... Is a good idea me thinks.
Or, like delphinium said you can explore the hills/woods/swamps for iron/redwood/mandrake. Since I need a lot of iron I always look for it when starting, yet last time there was none in the vicinity... none in 15-20 hexes! But I've got few hilly provinces so I wasted time exploring them...Result? 3 in 5 had iron deposits! I don't know if it's just luck or is the iron that prevalent, but this sure helps (economically too).