Always have all subs, magic, and weapons capped if possible for any melee job. That's the best way to assure repeat invites. If the party leader asks if you can plant hate on a tank post 60, or first voke for a NIN+THF party in the 30s or whatever, and you say no, you can bet that leader isn't going to invite you again if he has a choice. Just always be ready to help out with tanking, stunning, or hate management if the party needs it.
That being said, you need to experiment for yourself, DRK has alot of different playstyles, and what works for some people based on current gear or merits may not work for others. I personally did GA as /THF from 30 to mid 50s, then went /NIN with axes due to early access to rampage from full axe merits, then in 60-66 used guillo, 66 went /THF for SATA SS, due to the massive WS damage for closing light (and because /SAM was a HP sponge without seigan or dread spikes). Post-70, I used either /SAM or /THF depending on what I felt the party needed more.
But that's just me, you need to use the journey to 75 to discover for yourself the strengths and weaknesses of the job and how to excel at it.
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