On my first try I got killed in the first battle while figuring things out, the second I I think got through 3 battles but got ruined by an elf with high attack. I think maybe I also had low DEF because it was doing like 40 damage or something.
On the third try I killed 8 elfs. My strategy was to use Correct DEF (I don't remember the real name) right away so that I don't lose health to a high damage hit. Then just attack to try to learn whether it's necessary to correct any other attributes, like ATK or ACC or AGI. And don't let your health get too low without determining whether you need to correct MND to get good heals.
Assess Foe usually felt like a waste of a turn to me, since learning that the enemy excels at something seemed less important than correcting my own flaws ASAP. I felt like I got more information from just attacking (I can see if my damage is unusually low indicating a chance of ATK debuff, or if I miss indicating a chance of an ACC debuff). I didn't really play for high scores though, so maybe it saves MP over guessing Correct skills in the long run, and can help reach higher scores. After the 8th elf in my run I was out of MP so I didn't really have any hope.
The element of ambiguity in trying to figure out your weaknesses was the highlight of the game for me.