A lot of people like to rank the main trans skill first for the form changes. That’s not necessarily the most efficient order to rank them in, if you don’t particularly care, that’s fine. If you like efficiency you should probably read this section.
Paladin:
Spirit of Order: Adds HP/MP/Stamina and defense/protection. I personally don’t think ranking this is a priority unless you really like having more HP and stamina. Ranking it up a few times is a good idea though, so you can store more level’s worth of exp without worrying about accidentally wasting any.
Power of Order: Adds Str and Will. For warriors this should be high priority, don’t expect to gain too much will though.
Eye of Order: Adds Dex and Balance. Archers should make this skill the higher priority.
Sword of Order: Adds raw min/max damage and wounding. Rank this after ranking your high priority skill above.
Note that Paladins do not get Int at all.
Dark Knight:
Soul of Chaos: This skill adds HP/MP/Stamina. Not a priority in my opinion. As usual, ranking this a few times to hold more exp is a good idea.
Body of Chaos: Adds Str and Balance. A good combination since you can hold low balance weapons very easily with this. A priority for warriors. Note that three-fourths of the time you’ll get less strength than a Paladin of equal rank.
Hands of Chaos: Adds Dex and wounding. Very high priority for archers. Half the time you’ll get more dexterity than a Paladin of equal rank.
Mind of Chaos: Adds Int and critical rate. High priority for mages. Mages will want to become a Dark Knight since Paladins do not get Int. Half the time you’ll get an average roll on Int.
Control of Darkness: If you’re ranking Taming you might want this, most of the time people leave this untouched until they have nothing left to rank, though.
Dark Knights do not get Will at all.
Falcon:
Fury of Connous: Adds HP/Stamina along with Str and min/max damage. If you are a melee elf you will actually want to rank this first, otherwise this is not a high priority skill. Rank this after your high priority skill listed below if you are an archer or mage.
Armor of Connous: Adds Will and protection. If you like to be tanky you can rank this, otherwise you don’t really need to rank this early.
Mind of Connous: Adds MP and Int. Very high priority for mages considering that mana and Int come together in the same skill. Makes you very tanky as well if you use mana shield.
Sharpness of Connous: Adds Dex, critical and balance. Very high priority for archers, considering the combination of stats that this skill provides.
Elven Magic Missile: Basically an AoE crash shot/magnum, dealing between 230% to 600% damage to a wide area depending on the element you roll. Campfire bonus will boost damage to fire and lightning, but not ice. Wands do pathetic damage with this skill, don’t rank this if you’re not an archer.
Beast:
Daemon of Physis: Adds Dex, min/max damage, and balance. If you are severely lacking in balance then I would recommend ranking this up a few times, then you can leave it alone for a while.
Shield of Physis: Adds HP and protection. If you like being tanky then rank this. Giants actually get a lot of HP from transforming (not as much as DK), if you want some HP then go rank this a few times.
Spell of Physis: Adds Int, MP and critical. If you’re a mage giant then you’ll need this. Note that the mana boost for giants is very poor.
Life of Physis: Adds Str/Will/Stamina. High priority for melee giants (which is the vast majority of giants).
Giant Full Swing: Launches a super lethal AoE Smash that lands crits windmill-style. Can hit up to 970% damage at rank 1 with a fully charged, perfectly timed swing. Requires a two-handed blunt or axe weapon. If you don’t use those weapon types, you’ll just deal 100% damage (basically a normal attack). If you do use the proper weapon, then rank this.
Passive defenses:
Personally I rank passive defenses last, as they won’t be required if you can avoid getting hit in the first place. I prefer Heavy Stander first, then Natural Shield or Mana Deflector based on your preference (or rank all three equally, that works too). Dark Knights in particular have lesser melee auto-defense (20% for DK, 30% for everyone else) but much stronger delay reduction against magic and ranged attacks (60% for DK, 30% for everyone else) meaning Dark Knights can run into normal ranged attacks and bolt magic and take very little stun.