do you folks find that meditation and / or other calming / relaxing exercises helps one have a more positive trip?

I used to "prepare" for my Rue journeys in various ways because I felt that would make the experience more profound. Fasting, drumming, meditation.. Once I even climbed a mountain before drinking the tea (not joking - turned out great actually).

But I also drank it when I was in a very bad mental place, with no preparations, when I didn't care what I eat (although my diet is usually quite healthy - lots of fruits, seeds, no junk or processed food, no sodas etc). That was this summer when I started combining Rue with my usual Cube dosage (which was 3 grams, 1-2 times a week). I was a complete mess, with everything falling apart so in the beginning I used the psychedelics just to escape reality.

Now when I dealt with many things that were holding me back since childhood, I go far deeper. What I mean by that is being completely taken into the timeless motionless bliss which I feel is our real nature, but it's kind of pointless even trying to describe it. IMO that's something you can't achieve with for example a diet or preparing, and I think it requires hard work over a long period of time. So mind altering substances are only a TOOL, not a cure, nor do they improve anything without your own effort. After you realize that, consciously dealing with issues becomes your second nature and you don't need anything to "push" you to do it anymore.
I don't feel a need to take Rue so often, now it's every few months. My dosages also changed. Before I used 3 grams of Cubes, but now more than 1 grams scares me like nothing else. I also never take shrooms alone anymore.
Rue dosages have increased, and I use it alone sometimes. This way it keeps me aware and doesn't mess with my brain so much, which is something I prefer nowadays.

But even now diet or meditation etc don't make any difference! But what makes the difference for me is two things:

1. Intention I have prior to experience. Now I take it only when I need to sort some parts of my life, so I enter the day of the experience with a strong intention to deal with it. I approach it much more seriously than before, but without any superstition, trying to be humble but realistic. That way I make the most out of it.
Also, once I used it to "test" how far Rue can take me and it turned out to be a very bad idea, although the dose was regular. It transformed me in all kinds of creatures and I could "control" all my senses, for example I could turn off or change colors, sound... I wanted it all to stop so badly I even thought of suicide, for which I wasn't capable in my half-paralyzed state. So in my opinion intentions and what you expect of the experience make a really big difference!!!

2. How I treat others, what I mean by that is all beings, not just humans. If my consciousness is not clear, experience is much more shallow and keeps me in a loop for a very long time. Not very amusing nor productive.

Speaking of fasting -it's a bad idea IME, I feel very exhausted during such journeys, and true visions kick in only if I decide to eat something - usually it's a banana, my perfect fruit when altered it's peels contain tyramine, but I also ate cheese before rue and never had problems.

I don't think it works the same for everyone, and this all is based strictly on my own experience, but I still hope it helps

Absolutely, without a doubt. For me, its usually all about trying to enter the psychedelic state while in as calm and coherent a consciousness as possible. The better i do that, the more coherent, meaningful, mind blowing, and tangible the experience seems to be.

A bit of yoga followed by meditation before dmt is a beautiful thing. I usually don't even do it without some calming pranayama type stuff first

I find a nice colon cleanse before any psychedelic greatly enhances the experience and reduces my worries about digestion issues during the trip.

As far as sex goes, I find that pent up sexual energy can negatively impact the trip. For example, when I'm pent up, I sometimes get lower back pain.

interesting question. First there's the mental preparation, which i think best to just focus on letting go not having a "god head experience", try not to go in with expectations or give in to astonishment as mckenna often said, thought will hold u back. Meditation is also an amazing tool, as is intent.As for the physical preparation i found a big difference in what i eat towards how it effects the trip but much more so for oral preparations than smoked dmt. Found if i eat a lot of crappy food the body is more heavy so sort of like an anchor and same with sex. Sex is like putting the body thruogh a tornado and many shamans say and i found truth in it also has a lot to do with smells and communication with the spirits. The more healthy i am and more abstain from sex the more a kind of sweet smell emanating from the body and it is your smell that can attract or detract certain kinds of spirits. Also besides supplying more vital energy , sensitizing you to the plants/substances, abstaining from sex and certain foods, i found the spirit able to easier roam free because it sort of loosens the ties between the physical and spiritual bodies. These points are why i think all the restrictions exist in traditional dietas. But again this is more for oral preparations and none of it is required for a god head experience just in my experience found helped.