You can generate a good starting .config with make localconfig which creates a .config which prepares the modules which are in use by your system at that point. You can also get the old kernel config from /proc/config.gz which is probably a better approach.
I would guess that the approach described here is pretty much distro-agnostic.
Anyway, compiling the kernel:
mkdir ~/tmp cd ~/tmp wget http://www.kernel.org/pub/linux/kernel/v3.0/linux-3.8.2.tar.bz2 tar xvf linux-3.8.2.tar.bz2 cd linux-3.8.2/ cp /proc/config.gz . gunzip config.gz mv config .config make oldconfig make -j2 make -j2 modules sudo make modules_install sudo make headers_install INSTALL_HDR_PATH=/usr/src/linux-3.8.2 sudo cp arch/x86_64/boot/bzImage /boot/vmlinuz-3.8.2 sudo cp System.map /boot/System-3.8.2.map sudo mkinitcpio -k 3.8.2-ARCH -c /etc/mkinitcpio.conf -g /boot/initramfs-3.8.2.img
NOTE: the naming isn't random. In order for grub-mkconfig to discover both the vmlinuz and initramfs files they need to be named vmlinuz-IDENTIFIER and initramfs-IDENTIFIER.img. The identifier can be anything.
Generate your grub.cfg:
sudo grub-mkconfig -o /boot/grub/grub.cfg
Reboot, and do
uname -a
Linux titanium 3.8.2 #1 SMP Mon Mar 4 20:17:17 EST 2013 x86_64 GNU/Linux
