If you want it to last, and if you need to ask the question in the first place, then the answer invariably is usually no, do not overclock it. If you ARE going to overclock it, there are plenty of online tutorials on overclocking graphics cards in general. Hundreds of them in fact.
The question really is, do you NEED to, and if so, maybe you bought the wrong card.
What are your full hardware specifications including what resolution and refresh rate your monitor has, CPU model, motherboard model, memory specs, exact power supply model, etc.?