Guild Wars 2

How would I increase my agony resistance? I have 87 +1 Agony Infusions.

You combine those infusions, and make a larger Agony Resist item.

There are 2 kinds of Agony Resist.

Simple and Complied.

Simple Resist Items are in Every Ascended Item and Designated as “Defensive, Offensive, Utility” They come in +3, +5 and +7, As well as +5 and + (Stat).

You can Buy Simple Infusions, from the Vendor in the Fractals, Laurel Vendor, and WvW Vendor.

Complied Agony is Designed as “Agony Infusion Slot” This is only available for Rings (Infused/Attuned), and Back Item (infused).

Artificer Trade Skill is what Complies Agony Infusions. You can start Combining at 0 ranks and It works pretty simple.
You combine a +1 and a +1 with a Regent, and you get a +2.
You combine a +2 and a +2 with a Regent, and you get a +3.
On up that way for as high as you with to go.
Typically the highest you would ever need to go is +11.

You can buy Regents from the Artificer Vendor at 10 for 14 silver.

Hope that helps, if you have any other questions, let me know.

The wiki ist also very helpful on this matter: link