So I am hardly an expert, so hopefully someone else pops in and offers more help, but I've been working a lot with Robin lately trying to improve and here are some things I've found
-Arcfire is your best combo starter and has good damage output, I use it often.
-as great as a fully charged Thoron is don't be afraid to use the earlier ones for quick damage and to help set up some breathing room.
- The Levin sword makes their aerials fantastic with good kill potential.
-Nosferatu has pretty bad endlag so try to use it only in combos or if the opponent won't be able to counter (i.e. counter spamming)
-the new jab combo is pretty great and can be done to buy time while your books/sword recharge.
Hope this helps!