Well to me it seems like you don't spend a lot of time thinking about pvp strategies and just go with skill spam and hope for the best.
heha knows his shit, because he's been playing for a long time developing his skills and strategies.
1st thing:
You can force the use of gtb shield on any player simply because your magic dmg is ridiculous.
2nd thing:
You can strip shields using D.War card
3rd thing:
Even if your opponent is using FCP you have energy coat and access to a lot of redux like beret/poopoo hat, skull aura, sacreds, fluffy wings etc etc.
Final note:
Find a good balance between redux and dmg output to wear your enemy out untill their fcp dissipates then strip them and give them the meteor storm spam of their life. If you have any decent gear you will only need 1-2 hits to kill people on 1tgk.