The planning part should be a most important part, behind when you get experience the fruits of all your planning. Our first safari was in 2013
I would suggest writing down on paper those things that are important to you and what you would expect for the first time experience.
Talk to friends that have traveled and hunted in Africa, pick their brains and that will add to your list.
How I planned my first safari was to go with my list to Dallas safari convention and I walked around the first day and talked to everyone and collected the brochures,
asked my questions. My single most important to me was "What is the contiguous size of your property?" I wanted at least 60,000 acres. Then I wrote notes to myself on my impressions of the outfitter and went back to the hotel and compared those that gave me the best impression at a personal level and what was on their brochure. I broke the large number down to like 15 and went back the next day and asked all the rest of my questions. ie (lodging, meals,what to bring, is it a malaria free area, what shot will I require before coming over, what is there to do for non hunters, and all the questions about the game available, costs, taxidermy etc) I reduced the list down to 3 and went back on the 3rd day and just talk to them and watched how they interacted with people first thing in the day to end of the day. I then returned home and started emailing and calling references. Doing Internet searches, looking for good review that went into detail on their experiences. then started to conversation on booking my safari and putting down a deposit and locking in the days. I chose to go during the kudu rut period on the dark phase of the moon. My better half had a blast and became a huntress while there. My army buddy and his wife and youngest son also came along and we had a great first safari. We also did a photo safari in Kruger Nat Park. The only thing I would have done different was to do the photo safari first. We do a long motorcycle trip every couple years but while waiting for the plan in Joburg to come home the ladies came up and said the motor cycle trip for 2015 was now 2017 and we were coming back in 2015 for cape buff for me and my buddy and the ladies have a list of plains game we didn't get the first time that they want to hunt. So this year at SCI I had help of 3 others to help ask the question and form their impressions. So the 2015 is booked, loads for my 450NE and my better half's 7x57 are locking in and much practice getting ready. Have fun planning and enjoy the first safari