You should train your SG officers and membes as soon as they're elected. Ideally, there should be regular training in almost every SG meeting throughout the year. But most Student Governments have one training retreat in the summer/fall after the e-board elections. More progressive and evolved SGs often have two or three retreats throughout the year.
ASGA recommends constant training. In every discipline, from atheltics to music to art, practice makes perfect. We must practice being good at Student Government. And we must constantly train if we're going to be great at representing our students.
ASGA's MISSION STATEMENT:
The American Student Government Association will provide all Student Government leaders and advisors nationwide with networking, research, and information resources and will teach them how to become more effective, ethical, and influential leaders on their campuses. ASGA also will promote the advancement of SGs, conduct research as the nation’s only “SG Think Tank,” and advocate the importance of having a vibrant, autonomous Student Government organization at every institution in America.