I remember when I saw Shal jumping off one leg - it definitely clicked something in my mind in terms of how much more speed I can use and power. If this guy can do it, I can do it too! And I could feel it inside that I could do it, just not at this strength level. But I could feel it - I usually don't feel it when I know I can't do it, but in that case, I knew I could jump like that.
Once you witness real jumpers first person, you kind of start to realize it's possible for you too.
For me personally, when I participated at the dunk contest in 2006 here in Romania, in order not to get jelly legs, I kept all this arrogant attitude inside me, you really have to have swagger and think you're better than anybody and can't wait to show that to the world. That's the mentality you need to have and really believe into.
You should be like "I've trained for this, this is what I want to do, I'm going to kick yo ass". Also, although it might sound silly, you can/need to swear a lot in your mind. Because using "bad" words kind of makes your swagger increase. It's all psychological.
In a fight for example, when you swear at the other guy, you kind of prepare yourself mentally for the fight because you're "ready" and you can afford to swear at that guy so that means you're stronger than him, since you can afford to do that. There's a whole mental mechanism at the base of all this stuff so I thought about sharing it.
PS. Like I said, you have the structure, you said you don't have the strength to jump off one leg (I was like WTF? - since you're much more stronger than me and much lighter at the same time). If I can jump 34 maximall off one leg you should go near 40 or so.