In my experience, you should better focus 1-2 months on your preparation and have a very stringent preparation plan rather than practicing for many months.
Limiting your preparation time allows you to
- stay motivated during the interview period
- be authentic during your interviews (rather than making visible that you have covered your ability by learning cases by heart)
To enable a focused and short preparation time, I would suggest these FOUR PRINCIPLES:
PRINCIPLE 1) Start with a real interview process at a consultancy which is your fourth or fifth preference early on => This enables you to focus on your specific improvement areas early on rather reading a lot of broad material
PRINCIPLE 2) Always prioritize real practice (e.g. at Preplounge) over reading about case cracking theory
PRINCIPLE 3) Invest some time (or money) in finding high-quality case partners for practice
PRINCIPLE 4) Don't prepare more than others but prepare differently: Consulting is a people business, we want to see that you are a personality who is able to differentiate from the masses - why not e.g. reading articles from MBBs on a topic you like and reference it during the case/personal interview
I hope that helps! No need to get nervous if there is only 1-2 months left before your interview processes :).