[PvK]

Aw, I like Ulm!

Then again, my reasons aren't because I think it's stronger than others.

It does have the advantage for new players of having not so much to learn. If played against an equally-new opponent, this could be fine.

1 What are my best troops, strengths, weaknesses?

Good armor and forging bonuses are the main strengths. All the troops have pros and cons. Weaknesses are lack of magic variety and not very high morale nor magic resistance.

2 What sort of pretender is Ulm successful with? Any specific examples, or general hints?

I've had good luck with a dragon... against the AI, anyway.
Ghost King with many paths at 2+ can be good, especially with Iron Faith.

3 Are there any strategies, magic research, or item forging levels I should be looking to reach quickly?

Construction to take advantage of your forge bonus. Earth Boots and Dwarven Hammers. Try to find and conquer provinces with independent mages, so you can add magic paths to your arsenal to cover that weakness. Druids, Amazons, Wizards, etc.

4 What sort of armies should I build? (unit combinations)

If you hire arbalests, set them to fire at archers or rearmost, to avoid hurting your own men, and/or deploy them in armies different from your armies with infantry and knights.

I usually hire few if any arbalests, and most armies are a variety of infantry of Ulm, with independent shortbow archers for support, since they will rarely hurt your well-armored infantry. The infantry needs to have enough men to be a solid rock, and should be accompanied by other independent recruits who serve as fodder and distractions.

Knights can be good, but I wait until I can afford them, and then use them as flank strike Groups to complement the other armies, rather than by themselves or as direct assault forces, because that way they tend to die without doing much more than they cost, if that.

Level 3+ priests can cast Surmon of Courage to help keep your troops from routing.

Be sure to include enough troops - the more you send, the less fatigue will build up, and the less likely they are to rout.

Troops with shields are better at withstanding arrows.

5 What sort of armies/nations should I be afraid of? What sort of "" will I stack up well against?

Your Ulmish infantry will do well against most standard humanoid troops.

Against enemies who are well suited against your national troops, deploy something besides your national troops! That means using independents and summons or whatever else you can muster, against things that ignore armor such as poison gas, soul vortex, etc.

Some veterans will say that troops like Ulm's are useless once magic has been researched high enough, and say how that's only a few turns into the game. I think they are exagerating, especially if your opponent is a new player.

PvK