At this low level, particularly wiht undead you should try techniques: Horology, Traveler, Numerology..

They don't require MP and are the only ranged, party wide attacks you will have till you buy Fira, much later in the game. Bows and magick only hit one foe at the level you are at, while Horology or Traveler will weaken all foes in range, fliers included

First Aid is also good: Heals 1/4th of max HP without consuming a single MP.

And don't forget Libra to make those traps visible