As a lvl 50 SMN/ACN/SCH I still consider myself a noob at times and I am always willing to learn to better myself for my party and my FC - Metamorphosis.

DOT!DOT!DOT! My role is to spread the DOT all over the place and keep it spread all over the time of the battle.

Opening with Shadow Flare, with the basic macro of BioII/Miasma/Bio following immediately.
This basic macro is the staple of my DOT.
I amplify this with Virus when possible. Bane is my go-to for mobs to make it easier for the party.
Fester is my main single-target and high-damage skill.

My Ifrit/Garuda always gets Spur when it is available and I throw in Enkindle early on in the battle for single enemy bosses, as it is likely that it will become available later on when the additional damage is needed.

If I die, I die. I am more than happy to accept that it was my fault and will gladly lie there and wait to be raised when it is possible.
I also have Physick if need be to look after myself and my pet. I do not rely on the healer for my well-being, they have other things to concern themselves with.
If I see the Healer getting whacked by a mob I will always run and try and assist by drawing enmity off them and throw in a heal or two.
I see my role as Damage Party Support.

As always, let me know if there is anything I can improve.