I used to plan out my trips, but I found that that can sometimes lead to disappointment, and at the very least it always alters the most natural flow that the trip could take, which is very important to have, in my opinion. Lately, I've been tripping any time I feel strongly that it would be a good day/time to do so. That way, my mind has prepared itself. You know when you just wake up and your energy feels so positive, and you just know that today is going to be a good day? Well, when that happens and I also have a desire and opportunity to trip, I do it. The result of this is that my trips have been much more fulfilling and in a way more personal lately, and also 99% free of anxiety or negativity. It has helped me to appreciate just existing in the altered state, instead of trying to make something happen and then missing out on the whole experience.
Also, before tripping, I always make sure to have eaten something, but at least 4 hours beforehand, or hopefully 6, and not a large meal. I make sure to meditate/center myself and ponder on what I'm about to do before ingesting any psychedelics. I make sure, if I'm going to be inside, to tidy up a lot and get everything I may need on hand.