Gotta agree with you Xork...
I know, when I take a psychedelic, that I'm in for a less than predictable ride. It's not like I get the fear leaning over a line of cocaine, or at least, I never got the fear leaning over a line of something that might've had a bit of cocaine in it back when I did that sort of thing...
But taking a psychedelic is different. Once I've ingested, I normally change my mind about trippng, & of course, it's too fucking late! So anxiety is pretty common during come-up for me & one of the most likely anti-dotes is indeed, the outdoors! Getting outside into the fresh air, preferably under some warm sunshine, at a park or in a forest distracts me from my fears during the come up & once that's out of the way, I'm good to go. Despite the fears, I've never really had a really bad trip. I've had some bloody uncomfortable trips, & I've had some very bad moments during trips that have fortunately been resolved during the trip. But never a bad one from start to finish...
The only other thing that helps with come-up anxiety for me, & this is particularly effective with long come-ups, is the other thing Xork suggested, which is meditation &/or deep breathing, relaxation excercises. These seem to work better with longer come-ups because more time is available to reach a satisfying mental plateau before the drug begins to work on it. I've had some very energetic trips on Al-Lad, for instance, at gigs, or out trekking, but when I first got it I was using it after an hour or so of deep breathing & those trips were amongst the most relaxing I've ever had & produced in me a love & respect for Al-Lad that I honestly don't think I have felt for any psychedelic in particular before now. I like tripping, I LOVE Al-Lad.