There are different ways to do this, e.g.:
1) Use a status effect that gives a bonus to the status value and add that in your attack (ability). That'd also allow you to automatically remove it after a turn (or whatever duration you want).
A stackable effect also allows to accumulate multiple bonuses.
2) Have the attack (ability) increase the user's status value (user changes, or target changes with switched user/target).
3) Do this in the schematic animating the attack - i.e. changing status value or status effects there. You can also add that in a separate schematic and add it to all attacks that should do this.