Olaf,
I am far from a vetaran, but I will share some of my tactics also.
I like to cull those with bad afflictions, including diseases from my main army. You will laugh...but I just put them a decent distance in front of my main force and let them advance while my main army often holds and attacks.
You don't have to allocate too many units for your screen to draw archer fire. So I do get some use out of them. I've been playing a lot of Ulm, so it's rare that fire from anything short of crossbows or maybe Man's longbows bothers this group.
I've been using archers to one flank with good success except when someone puts cavalry on the flank... My little shortbow archers don't tend to do very well against shielded, well-protected cavalry. And they will often all fire at even one cavalry unit, more often than not hardly damaging it.
I find that it is easy to distract archers without specific orders.
What I truly love about this game is that there are no right answers. There are things that don't work well in combination...like Caelum and a heat scale...but there isn't really anything that can't be countered with good planning. I bet if you came up with a pretender and nation setup, including scales, and told Gandalf Parker or Zen what you'd come up with...each one of them could design something that would counter that pretty well. And I also bet they wouldn't come up with exactly the same thing.
You are right about the magic. There is a lot to familiarize yourself with, and some of the spell descriptions leave things for you to discover. If you would like more detailed descriptions, Sunraybe has an excellent site that I would highly recommend for beginners like the two of us.
-SM