New to tanking

[Tint]

the stats are Critical Hit > Determination > Skillspeed > Parry

Crit and Det are the only really good ones. Skillspeed has it's uses, but you will drain your TP faster and it doesn't affect your magical attacks (Unmend, Unleash, Abyssal Drain).
Parry is completely lackluster. It has a low scaling (getting tons of parry doesn't affect the actual parry chance noticeable), it is random (but you need to mitigate, so you have to use def-cooldowns anyway) and you can only parry physical attacks (so it is useless against magic attacks). parry is also useless as Off-Tank, because to get a use out of parry you have to getting hit. so Parry is the worst stat, you should avoid it.

as a tank you also want to meld Strengh into your accessorys. because tank accessorys only have Vitality, but your damage scales from Vitality and Strengh (you can't overmeld main-stats, so you have to put the Strengh materia into the first safe-slot).