15 hands isn't really enough to draw any conclusions about a player - you could be marking them as loose/aggro when they're just getting a good run of cards, for example.
That said, some of the stuff I note is...
- Tight/Agg, Loose/Agg, Tight/Pass, Loose/Pass (for pre and postflop).
- Minbet = strength/weakness?
- Overbet = strength/weakness?
- Does/doesn't usually bet draws.
- Does/doesn't chase without pot odds
- Overvalues pocket pairs - yes/no?
- Bluffs - never/rarely/often.
- Attempts blind steal - never/rarely/often.
- Defends blinds - never/rarely/often.
- Good/bad/average player overall.