How to have effective prep sessions for interviews?

Let me give you a little background first. I am a sophomore at a non-target. I worked at a regional IB last summer and will return to the same one again this summer. I am getting ready for the 2020 recruiting cycle for junior summer. Previously to prepare for interviews, I was just sort of going through the 400 question guide by writing out and practicing my answers. The seniors in the finance program recommended I do something else. My school is non-target, but we still place well for the guys who are actually serious about IB. Our senior class has guys going to best EBs (Moelis, Lazard, Greenhill) and BBs across NY, SF, CHI, and DAL. We also have a strong amount going to the good MM banks too. They recommended that I work through the questions with other guys recruiting, and then periodically do mock interviews with them. For the last 2 months, I have been prepping with other sophomores getting ready for recruiting. The only issue is that I feel like we're just randomly going through the guide. I want to get an actual schedule and agenda going. Does anyone have good insight on how they have done prep with other guys? Do you guys have like a system or plan that has worked well?