David Frum offers some:

Giuliani faces one severe obstacle to the nomination: He is pro-choice in a pro-life party. He cannot afford a second obstacle. Giuliani has to move now to align himself with the Republican voting majority on the immigration-reform issue. Immigration is a huge concern for Republicans in South Carolina — and given Huckabee’s dismal record on illegal immigration, the issue offers Giuliani a chance to do well in what might otherwise look like a natural Huckabee state.
If Giuliani can beat the odds in South Carolina, he will be superbly positioned to start amassing big delegate totals in Florida, California and New Jersey, when those huge states come into play in February.

That advice echoes that of NR’s editors. (I don’t buy most of Frum’s analysis about why Giuliani has a better chance of getting the nomination than McCain, but it is a useful corrective to the premature obituaries Giuliani has been getting.)