By pitching out loud to myself a few times and recording each attempt I was able to transcribe the best bits, and cut things down until I had a simple and clear version of my pitch. Then it was a matter of memorising it. I repelled at the idea of memorising a pitch at first because I was afraid of becoming too stilted and robotic in my presentation, however the opposite was the case. By memorising my pitch, I found my anxiety decreased dramatically and I knew exactly what I wanted to say. This gave me the freedom to connect with my audience and focus more on the way I was pitching the material, and less on what I was pitching.
The other big lesson was learning not to judge myself as I pitched. Whenever I catch myself wondering if I'm doing a good job mid-pitch, I loose my train of thought and things fall apart. By believing that what I have to say is exciting and engaging, it often comes out that way. But when I doubt myself, everyone notices. I guess that's why pitching is such a challenge.