Well, my RDM is merit'd out like this.
HP/MP (used to have +30 +50 but i'm moving the MP ones to HP)
HP+30
MP+30
Group1 10/10
5/5 Wind Acc
5/5 Ice Accuracy
Group2 6/6
Lv3 Slow II
Lv1 Blind II
Lv1 Para II
Lv1 Dia III
Magic Skills (16/16)
8/8 Enfeebling (Did this before they updated the total)
8/8 Elemental (Did this post-update when the total was raised)
Attributes (You can do these as you please, some don't do MND at all, and do STR or something, if your not just a mage)
3 MND
2 INT
Other
Crits 4
Spell Int Rate 4
Basically, do the other ones as you see fit based upon your other jobs at 75 too. IE if you want to merit STR to +5 for a melee job then go ahead, merits outside of the Job Specific ones are all your choice

Merit Enhancing if ya want, its up to you, but the above is what i've done.