Skills are improved by spending Improvement Points or IP. The amount of IP needed to improve a skill is equal to 5x the current skill level. For example, to improve a skill from level 5 to level 6 costs 25 IP.
There are no skill improvement modifiers.
Float IP are points awarded for good role-play, surviving extreme danger and completing main story lines or subplots. These points can be used to supplement the amount of standard IP used when improving a skill. Note that Float IP cannot pay 100% of the cost of improvement. A minimum of 1 point must be from standard IP.