'There is the known and the unknown, and in between...
The Hebrew word for fear is 'Yirah', and the word for vision is 'Riyah'. Kabbalah points out that these words share the same letters to intimate that fear and vision are strongly related. On the one hand, vision evokes fear, as when a person sees a dangerous animal or imagines a terrible disease. On the other hand, vision may allow one to overcome fear. This relates to why people are more fearful by night than day. At night it's difficult to discern objects and one can easily mistake a small tree for a person and a stain on a wall for a spider. One also feels insecure walking when they can't see what's in front of them. During the day, however, one clearly sees what things are, and walks without fear of stumbling.
In short: sometimes we're afraid of the known; sometimes, of the unknown.
When skateboarding, I experience both types of fear. Sometimes my fear stems from seeing how I can injure myself by attempting a dangerous trick. Personally, I heed to the alarm and avoid the trick till I'm better prepared for it. On other occasions, I'm fearful due to not knowing what to expect as I'd never tried the trick before. Here I attempt the trick incrementally. If I see that I can manage it, I progress, if it's too risky, I leave it for later. In other words, I slowly make the unknown known so that I can deal with it appropriately. Most noteworthy is where I feel panicky performing a trick that's not too risky - albeit difficult. This usually occurs when I'm not looking at my board while performing the trick and it remains in the unknown. By keeping my eyes on the board I find that my fear abates, I have more control over myself, and am better able to focus and land the trick. Watching the board while performing a trick has a remarkable effect: my skateboard - as time in general - seems to slow down, allowing me to maintain composure and to better control the manoeuvre.
So conquer fear by making the invisible visible; by bringing daylight into the darkness of the night.
Or simply, keep your eyes on the board!