First off, a disclaimer: the following musings are my own and purely about gameplay. I like Bull as a character and others, veeia for instance, are far better at analyzing characters than me.
- Kill those Snowfleurs and Lurkers. Bull has the odd distinction of being both a warrior and glass cannon who gains greatly from being able to dish out critical hits.
Because of this he's better suited to wearing crafted rogue armour and weapons with multiple utility or offense leather slots (Sturdy Prowler Armour being the best in this regard).
Snowfleur skins allow him to wear rogue armour and Lurkers raise Cunning, which indirectly raise critical chance and ranged defence on arm and leg armour pieces.
- Ignore active Two Hander talents. For one, they can only detonate off of Paralyse but the biggest problem is that they aren't worth the stamina cost. Block and Slash however should be upgraded as soon as possible and set to preferred on the tactics menu and make a beeline for Flow of Battle which lowers cooldown times by a second with each critical hit.
- Turn the Blade and Turn the Bolt from the Weapon and Shield tree should help Bull survive a lot longer.
- DO NOT LET AI USE REAVER TALENTS. Much like Knight Enchanter and Assassin, AI sucks at using Reaver talents properly.
- Varric or an Artificer Inquisitor make the perfect partners in crime. I say this in part because I'm biased and my elven bull rider is an Artificer but mostly because they have a passive that raises crit chance as well as access to the best crowd control skill in the game, Elemental Mines (provided you have the right passives, Looked Like It Hurt, Opportunity Knocks and Cheap Shot being the big ones, and good crit chance),
The reason I say it's the best CC skill under those conditions is because they become spammable, have no friendly fire and sunder armour as well as being capable of poisoning enemies if you have Poisoned Weapons.
- Get Combat Roll and set it to preferred.
And once again, another disclaimer: these are things that worked for my Bull riding elf and may or may not work for you but I find that with Bull and Varric things seem to die much faster.
Just my two cents.