Trust them and trust yourself. Chances are if you're ready to do it yourself, you've done the skill a lot of times with a spot or a little help. Do the skill just like you've done it hundreds of times with a spot. Once you commit to doing a skill don't give up halfway through. Follow through with the skill until the end.
Injuries occur most often when an athlete gives up halfway through.
One other thing that can help you to overcome your fear of a skill, is to perform the skill over and over in your head. Take a couple of deep breaths, close your eyes and picture yourself doing the skill a number of times in your head successfully. This will help your confidence and help you to imagine exactly how it will feel. Lastly, being well rested and eating a good diet to keep up your energy will help you to feel strong and alert at practice or competition. The stronger you feel, the easier it will be for you to successfully perform those new exciting tricks.