I just learned how to convert items to materia

[MaethusXion]

Generally they'll be 1 of 3 types, from what I've seen:

1-Relevant to the type(ie, GLA/MRD weapons & gear dropping Parry or VIT)
2-Elemental(self-explanatory)
3-Semi-Relevant(ie, Skill/Spell Speed, Accuracy, Determination, Crit)

Basically, DoW items should not drop MND/INT/PIE or GP/Gathering/Perception or CP/Control/Craftsmanship materia. DoM should not drop VIT/STR/DEX or DoL/H materia. DoL should only drop Elemental or DoL materia. DoH should only drop Elemental or DoH materia.

Should being the key word, there's always bound to be a fluke somewhere. I remember not getting anything good from a convert in v1, but then again this's a much different game now.

Also, you need something of relevant item level. Something iLVL1 will never drop anything above a Grade-1 Materia.