Start off at default voltages and find the highest overclock at default latencies, unless you know that the ram will run with faster timings, for example, from reading reviews or posts by forum members, then use those settings. Regardless, the point is to find the highest ram speed at the selected timings. Upon loosing stability (test with Memtest), your choices are to increase voltage to see if the ram stabilizes, or increase the timings. Which way you go would depend on at what speed you are currently running and how fast you would expect your cpu to run. If for example, you are using a cpu that will (or is expected to) top out at 240 and you have reached 210 at your current timings and voltage then it is doubtful that increasing the voltage will take you to 240 unless you are using something with bh-5/6 and you have lots of voltage at your disposal. Assuming that is not the case then you would choose to relax the timings and continue increasing the fsb, aiming to reach your expected goal of 240. When you get close to your goal and you experience instability, the raising the voltage could help you stabilize the ram and allow you to reach your 240 without having to reduce the timings further, if not then you continue the process. Remember that increased voltage results in increased temps for the ram, so in some situations you may need to cool the ram with fans, etc. Once you have reached the max cpu speed, you would then attempt to keep the same speed but speed up the timings by increasing the voltage. You are looking for that sweet spot where the ram runs as fast as possible (limited by other components or itself), at the lowest possible timings with the least amount of voltage. It is just a gradual process and requires time and patience.