My relaxer is in two days and this is what I did tonight to help prepare: I lightly detangled my hair, sprayed Sta-Sof-Fro to my roots/newgrowth, and heavily moisturize/seal.
Sta-Sof-Fro is an old school product that I remember seeing under the bathroom sink as a little girl. It is very moisturizing, but too much can cause mushy hair (like the time I used it as a leave-in conditioner). It does a great job of softening my newgrowth, so it will be more manageable on relaxer day. I spray my roots two days before to ensure that my roots and scalp have enough time to dry completely before the relaxer application. I buy Sta-Sof-Fro from Walmart.