There are some other nice guides for overclocking the i7. Study some of these guides, not just read them.
In a nutshell - 1) set the RAM multiplier to its LOWEST value, 2) start by gradually increasing the base clock, (raise the CPU voltage slightly as necessary - never exceed 1.375V) - watch temps closely (30-35 degs C is ok at idle, and under 70 degrees C under load is ok). 20 degrees ambient.
Remember, overclock gradually; over several days - let the computer run for a while before deciding to go to the next OC level. Have fun.