On the other hand, Ulm usually has enough money to build a couple of temples. AFAIK, each temple would spread the high dominion, even if it would first have to fill up the province it starts from. Also, every temple stops enemy dominion from going further, even if the temple province's dominion can be lowered.
There is a great document explaining dominion in great detail. I think it's on
www.dominions-2.org, but I don't remember even its name ATM.
I think you did quite well in the army department, and did use your mages quite well. The fact that you used a support mage with a Golem was also very good. Just learn to use and look out for your dominion a bit more. It also helps if you know what priests can do for you, and knew little more of the Evocation spells, but that will come with different experiences. You're doing very well IMO, especially for a first win.