[Adept]

If everything else fails (of just to have some spectacular fun!) try a dragon.

Now that dragons have the +5 fear effect (I'm pretty sure they didn't use to) they can take on armies even though they don't trample.

Take a dragon pretender, boost with fire, air and earth if you want. Change him into dragon form and set orders to fire.

Send him alone to conquer provinces. As soon as you can equip him with amulet of missile protection and ring of regeneration, do so. Some type of helmet is also good. The horned helmet gives the dragon a much needed extra attack.

I tried this recently, lamenting the fact that dragons don't trample, and to my great success the fear (which I hadn't noticed) made all the difference. I conquered 12, independent strength 5 provinces, and trounced up some tough Ulm armies before finally being defeated on the gates of Ulm.

Definitely something to try if you have trouble getting started.