What’s important is;

Having some self-inquiry: What is my intention, what do I long for, what is my actual problem? What am I curious about?

Am I in a physically and mentally healthy state to drink Ayahuasca? (Read contraindications)

With whom do you want to undergo a Ayahuasca ceremony? Nothing is as vulnerable as a Ayahuasca ceremony. This requires a field (set and setting) where you feel comfortable, which starts with the process facilitator/ therapist / guide.

Once you have decided to drink and know where/with whom, you will start preparing yourself.
Mentally: by taking it easy 2 weeks beforehand. Give yourself more space and try to avoid a busy schedule.

Physically: by eating a plant-based diet and avoiding certain medications, meat, diary, sugar, spiced food, alcohol and coffee for 2 weeks before the ceremony. (Read more here).

A proper organization or process worker will provide you with the right preparations.