From the Japanese wiki:

Strategy: You gain strategies at certain levels and a few extra from "training," the amount you can gain from training is shown by the "special crash course operation" number. In other words it's one for 1 star, two for 2 star, etc. It looks like there are some strategies from training that don't affect the special crash course operation limit, but not sure.
-- Affection raises the chance your character will adhere to the strategy assigned.

You can check the JP wiki on the left where it says LV 10, 20, 30 to see if your character has comparatively good stats. Sadly the 4 star SMG I got from the pre-register event isn't very good. http://wiki.kanmuryou.com/shooting-girl/index.php

The best xp in the Tokyo district are the boss missions, with 3-5 being slightly better than the others.