You can also have a look at this website:
http://kernelnewbies.org/
What can you "Fine-tune"?
-> Remove all uneeded drivers: be sure to not remove the ones for your harddisk or IDE or SATA! For this you need a lot of details on what device specifications you have (lspci will tell you)
-> Be sure that your processor is the good one so that optimization are the best ones.
-> Change in the scheduler (type, HZ, ..) , memory management.
-> Network parameters (do you want ATM, ppp, RNIS, ...)
-> .. a lot in fact
I'm not sure you will see a big difference compared to a full kernel. The parts that you don't use are not loaded (modules).