diff -u is the most important thing. I don't even look at patches created without that essential flag (see linux/MAINTAINERS).

Lots of other flags also help, as genixia's pointed out.

All of the directory hopping done by make is kinda sluggish, I agree, and I think they've finally improved it a lot in the 2.5.xx kernels. But even with that, my 850Mhz notebook can rebulld Hijack from zero in just a few minutes.

Cheers