Guild skills are improved (“trained”) by spending exp and gexp. Costs increase for higher levels of individual skills and for more advanced skills.
Luckily, training skills can be done anywhere, not just in the HM guild.

Syntax: 'train'
Displays:

`.'*`-----------------'*`.'*`.'*`.'*`.'*`-----------------'*`.'
   Skill                   Level         Gexp           Exp
   extrapolation              1           210           157
   flurry                     2          2205          1653
   health                     1           210           157
   knife_hand                 1           210           157
   lore                       5          3780          2835
   manipulation               5          3780          2835
   power                      1           210           157
   resheph                    1          1470          1102
   sabda                     15          6720          5040
`.'*`-----------------'*`.'*`.'*`.'*`.'*`-----------------'*`.'

• Level - Your current level in the skill.
• Gexp/Exp - Cost for next level. Skills you cannot afford are displayed in red.

Syntax: 'train <skill>'
Trains the designated skill.