I usually just judge the damage by the amount of MP it uses.
If two of the same elemental attack that inflict damage to a single enemy are available, I would assume the higher MP cost of one over the other would mean it would do more damage. --- PSN: StuntmanSnake /// Gamertag: StuntmanSnake OUYA: StuntmanSnake /// YouTube: StuntmanSnake
Having said this^, it may be more efficient to then equip the lower mp costing skill, especially if the attack is aimed at a single enemy. For example, thunderspark will be able to be cast a lot more times than Thunderbomb, allowing it to deal more damage over time. This is especially true during bossfights and the solosseum.
Generally speaking, I recommend physical damage tricks over other elemental tricks, simply you get incredible high attack creatures to follow you, tricks such as having Slice n Dice, Drop Chop on the same creature to spam the tricks with no cooldown, and Earthsplitter for area attacks to soften an emery group.
My Bone Baron does over 700 -1150 dmg with Drop chop at level 99, while Ollie does a little less with Mornstar and Astra with more MP cost and cast time, this is even I have armed the two accessories that boost light attack, of course I do better against dark creatures, but his is generally speaking across the variety of creatures and bosses we have encountered. However it must be said that the status you get for your Ollie is random from each level up, I might have a bad Ollie (383 magic attack at 99, I remember I rolled a few 1's but I don't like to reload)
Ollie is your best magic attacker (you have the best spells even your status are lower than some creatures), if there are creatures such as the Bone and Cata doing at least on par damage compared to you, you want to leave the AI exploit this.
Healer - Raise spells such as Upsy Daisy, a strongest area heal and medium single ally heal ( don't go strongest single heal due to MP cost and leave room for the AI do an area heal soon, no doubt when you are in a situation that requires healing, everybody should had taken some damage).
Buff - War Cry only, I found that a lot of creatures who has the buff that boost your magic are not really magic attacker but healers instead, that means you would need to switch creatures in the battle, and if you just arm the skill on the healer and hope he buffs your mag attacker the AI usually buff himself. And if you are in a situation that needs buff you are in a changeling battle where timing your defend/ evade or eating +HP/+MP food are more important.
Evade buff is a NO for me, any fights that the evader would able to tank is an easy enough fight to finish it off. Tricks and spells are auto hit, only good defense / mag defense will do.
Status effect - Rock-a-Baby (area sleep) and Love-Struck (area confuse) could make some fights a lot easier. You could have one creature specialize on status effect for your general go-to. The Hooker-Donker or whatever he is called has both of these, otherwise he is a healer/ light elemental. But I don't have a status effect specialist in my team anymore.
Curse - Slow down target.
Yoohoo - As well as the Melody skill that draw attention of the enemies on to you. Fantastic skills, great tank such as the Paleolith with 4 stars movement can kite your enemies when combine with Curse while your team mates provide the DPS.. Once Yoohoo is in effect, the enemies would try to come close to you where they are less likely to use tricks.
Sabotage - Reduce defense, helps on bosses.
These are my recommended skills, I have one lighting mag attacker and have gave up all my different fire, water, light and wind elemtalsts, cos all other has been situational and never hit as hard as my physical attackers. --- PSN: zhi_long