Always start your planning process by making sure that you and your stakeholders are clear on the goals of the project. As you are making programmatic and logistical decisions along the way it can be helpful to reflect back on your goals to ensure that everything aligns. It is tempting to just jump in and start thinking through the logistics, but if you skip this step you may find that your plan doesn’t actually get you where you want to be.
The next steps is to think about the phases of “buckets” of work like planning, communications, events, training, etc. This can help you to break down the work into smaller pieces and then see how they overlap. I usually plan out each bucket discreetly and then sort my plan by date to see how things interact with each other. This will make your work more efficient because you can see how things align. For example, your programmatic plan will overlap with your communications plan, helping you be more strategic in getting the right information to stakeholders in the most efficient way possible.
I am a huge proponent of backwards planning. I used this strategy as a teacher to think about getting my students where they needed to be and have transferred that practice into my project planning. Start each bucket with the milestone(s) and then plan backwards. Maybe you have a big event that you are planning for, start with the event date and then map backwards to make sure you have all the pieces in place. I often find that when you start from the beginning and not the end, you underestimate how much time is needed to accomplish all of the steps in your process.