Going from 'E' to 'O': What sort of challenges did you face as a prior-enlisted officer?

In my very short career, I've had several troops come up and ask me what it takes to commission. I've been able to help them a great deal, but I wish I could know more. Specifically, I went straight to my commissioning source straight out of high school, so my perspective is very limited. In my opinion, prior-enlisted officers are some of the best I've worked with. For those prior-enlisted officers out there, what advice would you give to an eager E-4 or E-5 who wants to commission? What sort of challenges did you face, barriers you had to overcome, and what are some of the things that made the transition from 'E' to 'O' difficult? Furthermore, how would you compare your life as an 'E' to what it's like as an 'O'? Any advice you have is greatly appreciated!