succeeding in a business phd program

[serbia]

hi everyone. i know that there are a lot of resources online about how to make the most of graduate school, but what are the best resources you all have found? has anyone found any good resources relating to becoming a business phd? or maybe experiences from other students that have been through the program and thought about what they may have wanted to do differently?

i'm talking more about what one should do to succeed in the actual program, not what one should do to gain admission. i'd like to hear any comments/advice you have!