I was playing empire, figuring they'd be the best place to start.
1) I think​ right now my biggest problems I'd battle. I'm struggling with moving my units around and surveying the battlefield.
2) Might have more problems when I get into the nitty gritty of managing the estates and diplomacy.
3) Any reason to encircle instead of fighting a town when there's no walls?
1) Use P to pause the game in battle and give orders. Hold down mouse button so you can change to formation of your unit (tight block e.g. for ranged units, long lines if you don't have enough melee infantry compared to enemy etc.) as part of the move order. The basic plan should be having a melee unit line supported by ranged units/artillery in the back, ideally on a hill. Place cavalry on flanks and a bit of a distance to the sides and behind your lines, use them to intercept enemy cavalry and flank the enemy melee line and charge into it's back when it engages with yours.
2) Takes practice. Right click on a building in the drop down menu for new buildings that can be constructed to open the entire building tree of that settlement. Read through all the buildings and decide what you want the province to do (remember, all settlements in a province share all the buildings functions, except for walls), pay extra attention to ressource buildings/unique legendary and regional buildings and build the rest of the infrasctructure around them if they give recruitement bonuses. Specialize your provinces if you can e.g. for money generation, cavalry or artillery, ideally with regional buildings that gives bonuses. There is no point in having several recruitment centers for any unit type, it just wastes building slots.
Use the mod for tier 4 minor settlements to make the game balanced and the campaign AI functional.
Ah, and AWAYS build walls (the garrision buildings usually give them at tier 3) in minor settlements that are remotely close to the enemy, the AI loves bypassing strongholds and taking out weak settlements without walls in one turn.
Diplomacy takes practice, but ideally you want non aggression pacts always unless you plan to go to war with that faction (relationship boost), all the trade agreements you can get and defensive alliances if you think another one of your allies won't attack them. Only use Military Alliances if you really need them (e.g. no risk of them attacking one of your other allies) or if the faction is part of the settlements/provinces you need conquer, if they are your military ally/vassal they count for the victory condition, basically being a diplomatic victory.Confederate smart, only do it if it doesn't overextend you too much and a buffer state wouldn't be more useful and the payoff is worth it (e.g unique buildings).
3) See the hourwatch symbol? That tells you how many turns you need to siege for an auto-win without fight. See the skull symbol? That shows you after how many turns of siege the defenders take serious attrition damage. Usually after 2-3 turns of attrition the assault becomes a walk in the park with zero risk.
Also I recommend starting as Dwarfes, Empire is not an easy campaign (one of the hardest ones) and easily overwhelms you with enemies and things you need to pay attention to. Also the extremely varied and flexible army roster is not for beginners, there is just too much of it (6 types of different mages alone) and if you don't know what you do you will easily end up with a bad army composition. Dwarfs ease you into the game the best.