There are more talented writers and less talented writers, of course. What there are not, are writers who are unfailingly brilliant from the first moment they set pen to paper to the last manuscript they send off to the printer. Even the very best writers have, over the course of their career, produced some pretty appalling slop.-Megan McArdle
So instead of fretting that their copy won't be any good, I tell them what it took me years to learn myself: they should give themselves permission to suck. It is easy to begin once you have accepted that what you produce may not be very good, and that this is normal. They will get better only by writing - and this can only happen if they sit down and face the page.