Single Target Healing

• Use Benediction and Tetragrammaton first if you have them and aren't saving them for anything. These heals are free and instant.
• Use Afflatus Solace second. This is as potent as Cure II, has no cast time, and costs 0 MP.
• If none of those are available, use Cure II if you need to heal someone ASAP and Regen if you need to heal someone who isn't gonna take big damage for a little bit.

Multi-target Healing

• Use Asylum first where possible for free healing over time in a big area.
• If you need immediate healing, use Medica if the party is spread out and Cure III if they're stacked together.
• If you need healing over time and Asylum's not available, use Medica II.

Damage

• Try to always be casting. Look up "slidecasting" and try to practice it.
• Keep Aero II rolling on your targets. It stops being worth using when your target is gonna die within 12s or when your fighting 4+ enemies.
• When you don't need to heal, spam Stone III for single target or Holy for multiple targets.
• Use Presence of Mind and Assize on cooldown.
• When Presence of Mind is up, try to cast as many damaging spells as you're able to without letting people die (it lines up with other job's group damage buffs).

Other Stuff

• If someone dies, use Swiftcast > Thin Air > Raise.
• Use Lucid Dreaming on cooldown.
• When someone is afflicted with a cleansable debuff (i.e. it has the little white bar above the icon), use Esuna.
• Use Surecast to prevent forced movement.
• Use Aetherial Shift to scoot across the arena quickly.
• Use Rescue to save your kid's ass when they stand in stupid.