Good luck!

I got my CFI 2 months ago after preparing for 4 months. If you don't have an instructor or if you have limited time with an instructor to help you with your CFI, I suggest starting with the CFI PTS and go through the topics and write a lesson plan for each one. Compile them in a binder so you have something to show the examiner and also to use for your first lessons.

Get a pilot friend to sit in front of you while you teach them (if you don't have an instructor), that way, you can get the bugs out of your lecture methods. Don't take a day off, 4-6 weeks is a tough schedule. Even if you need a break, just go to exams4pilots.org and run through a 30 question practice test to stay fresh.

If you get someone else's students, in the case that you are replacing an instructor that is leaving, make sure you emphasize the basics with them: stall recovery, traffic pattern entry, radio communication and from my experience: "go around" means full power.

Have fun!