I'll help you a little...there is NO single guide which will tell you exactly how to overclock.
You need to read as much as you can in the Overclock.net's FAQ section and proceed slowly when making changes. It should take you a few weeks on a single rig to really understand how the major pieces fit together. Here is some info that I THINK might help.
When overclocking, the idea is to identify the bottlenecks and remove them one at a time. But, as you remove a bottleneck, you will introduce a new one and potentially corrupt a previous one. It's a strange balancing act.
From the top down (roughly...not necessarily in this exact order), these are the settings that you tweak and each item below is the next bottleneck in line you will have to deal with.
FSB = Front Side Bus. This is multiplied various ways to supply signals to the CPU, RAM and the support chipsets.
CPU Multiplier = Multiplier X FSB = CPU speed. So, if my CPU is at X8 and the FSB is at 400MHZ, then the CPU would be at 3.2GHZ or 3200mhz. The multiplier can be locked or not depending on the CPU and Motherboard. You have to research this setting.
CPU Voltage: As you increase the FSB and alter the multiplier, you increase the CPU speed. As you increase the speed, you increase the energy required. This setting will need to be bumped up slowly as you increase the FSB. Also, temperatures go up on the CPU die. That means you need to monitor CPU temps during the overclocking process.
FSB:RAM ratio: This is the speed of RAM in relation to the FSB. So, let's say you have DDR2 - 1000mhz ram. Your RAM is running at half that or 500MHZ. So, if your FSB is 500MHZ, you would have a 1:1 ratio. If your FSB was 250MHZ, you would have a 2:1 ratio. This ratio can be locked or variable depending on the motherboard and CPU combination
Memory timings: These are the actual internal "clockwork" mechanisms of the RAM itself. Each time the FSB clock ticks, the RAM is doing something. Getting data, writing data, refreshing all the data, etc...This is a long and complex topic. Read the FAQ's.
EDIT: As you increase the memory timing and the ratio, you will need to increase the RAM voltage as well. Each RAM chip typically comes with a voltage max warning. Try not to go over that unless you have additional cooling for the RAM.
NB Voltage: The NorthBridge is the main CPU to RAM conroller chip (also the PCIx bus). When increasing the FSB, RAM speed, and RAM timings, you may need to tweak the voltage to compensate for the increased amount of data flowing through this chip. Also, as you increase the voltage, the temperature goes up (just like the CPU). Additional cooling may be needed.
In general. I've found that minor FSB changes will not require any other adjustments. Just monitor the CPU temp and perform benchmarks (which heat up the system) to validate the stability. If you are happy with the speed, then stop. If you aren't, then be prepared for a long and tedious serious of reboots, frozen BIOS's, and other annoyances.
One more thing...when you are messing around inside the computer, unplug the power cord. There is a low voltage running inside the computer, even when it's turned off. Plugging in and unplugging stuff with this live voltage can damage MoBo's REAL fast.