Planning depends on the Hike at Hand.
A couple of examples of planning: Putting together mail drops and having a team/person responsible in sending. Have fall-back plans if the shipments need to be altered. Have accurate hike companion to be used, I usually keep an outline with me at all times, but have detailed ones shipped in mail drops as needed. I never start a long trip with untried gear and I always have several hundred miles on a pair of boots prior to starting. I would always keep another pair of broken-in boots ready to be mail dropped. Experience really helps when it comes to the planning and actually getting started. Take lots and lots of time planning at first. If you make a future of hiking, things will get much easier and you will be able to anticipate requirements for a successful hike much better. Never travel so light that you have to bum needed items/food from another hiker. Nor, so heavy that you end up leaving things on the trail or shipping back home the excess.