Apprentice set is the gear you want, Arcanist is ok but for the higher Trials, its the 6 set bonus of immolate that sets the Apprentice Set apart.
If you get a blue piece: Look for pieces with High Crit Damage followed by High Crit Rating
If you get a purple piece: Look for the above and also Ability Reduction.
Legendary pieces you want to look for Power or Haste as well as all the bits above.
Bear in mind you want movement speed on either your legs or boots, ideally both as your fourth stat.
Once you get into Trials, you are going to want a Tome over a shield for the damage increase. You need to be flattening your enemys befrore they have a chance to get close enough that a shield would help!
To work out if the one you have picked up is better than the one in your bags, look at the two number that the damage can be, add them up and then divide by two, this will give you an average damage. So you can have Tome A that says it is between 800 – 1000 and Tome B that says is is between 600 – 1100. Even though the 1100 sounds nice, it depends how many time you are actually hitting for that number.
On the basis of this, Tome A average damage is 900 and Tome B average is 850. So In this instance, you would want to stick with the one that may seem like it would do less damage, Tome A.
You can do the same thing with weapons too, until you get the named ones.
Named Weapons/Off Hand
Find weapons with high average damage to begin with until the named weapon drops. Work it out with the method above to see if that shiny new one is worth equipping.
You want to be looking out for one of two named weapons which are Mukraiser and Derdrie’s Resolve.
Mukraser will summon in some minions for you to deal damage.
Derdrie’s Resolve will grant you a chance for an extra attack.
This one you are just looking for a good one that has most if not all the stats you want on in. In the end there are two named ones that you can get your hands on.
Carnival Cape is one that you should equip if you don’t have the other named one. Eg: if all you have is a bog standard one and this drops, go for it as it gives you a boost to your Crit Rating.
Integralas Mantle is the daddy of capes. It should be equipped as a priority due to its ability rate buff. This means that at end game, your secondary abilities can be cases almost instantly after they have been used. If you are lucky enough to have two to choose from, pick the one that also has Ability as one of its basic stats.