What you should do is not think so much about "preparing for the checkride" and instead think about preparing to teach students. Remember the FAA is mainly looking to see if you can transfer knowledge and build skill in students, not regurgitate information.... so start thinking more like you already have your CFI and now you have a student dropping $150-200 per hour to receive flight training from you. That should motivate you to really be prepared. Assuming you do pass, you could potentially be teaching students that same day... are you ready for that? If not, then you shouldn't feel qualified to do the checkride either, and if you are then the checkride should be pretty straight forward.
Having just started instructing, I can say that applying all the fundamentals you are learning while preparing for your CFI are important and will make it much more enjoyable for you and your student.
Have a syllabus for each student, so that you have a plan of action to move them from where they are to where they want to be. ASA, QRef, and AOPA all have free private pilot syllabi you can reference. I find it better to refer to these while I build my own syllabus for each student, but it's important to write it down so you know what your goals are for the next few lessons. It's your road map to achieving the student's goals. Adapt this as you get a feel for the student's learning abilities and frequency of lessons, and weather conditions (obviously you cannot teach crosswind landings on a calm day, and ground reference maneuvers might not be a productive use of time on a calm day either). Having a syllabus lets the student know "what's next" and helps you to assign reading and videos before the next flight so that the student has relevant knowledge and a good idea of what the maneuvers will consist of. They will be primed and ready to learn.
Have clear objectives for each lesson and dont try to cover too many points in one lesson. It is much much easier to provide a professional and helpful lesson when you have a clear plan of attack. You will be more relaxed because everything is there for you and the student will appreciate the more professional approach and the respect for their time and money.
While you might have created nice multi-page verbose lesson plans during CFI preparation (and you should), try to condense that and build a simpler lesson plan for in-flight use based around those same objectives. Make this knee board sized so it's easy to reference in flight (in a word processor just set the page to landscape and insert a table with 1 row and two columns, this you can print and fold in half and it works well), you can make training notes on the back and save this in your training record for each student. Include the objective, demonstrations, and practices you'll have the student do on this small lesson plan. Include estimated times for each segment of the flight so you can keep track of the lesson's progress and keep it balanced, otherwise it's easy to spend too much time on one area to the exclusion of others when you're first starting out. Include notes about key talking points and common errors so you remember them during your demonstration and while critiquing student practice).
When just starting, there is nothing wrong with taking some time yourself to sit down with your lesson plan and talking through it to yourself, just like you did while preparing for the CFI practical test. That helps you think through how to explain things again and think about which illustrations might be useful and which ones just get you tongue tied and sound confusing. This gives you confidence as you begin to teach in the airplane because you've already been through the material and will result is a calm demeanor which will help your students learn and remain relaxed too (they follow your cues a lot).
Instructing is a lot of fun, enjoy it.
