I disagree, Aerbabe. I think the "good idea" is the hardest bit. But the rest of it is pretty difficult too.
There's also a Dawn to Dusk Half Competition - about four hours flying, either morning or afternoon, on a theme, otherwise similar to the full competition. This might be a more gentle way to break yourself in. Or for people like me, burnt out after three Dawn to Dusks, a saner way to do it. That's what I'll be doing next year. It might even give me time to enjoy it.