How to take a clear picture of the moon with my Nikon d3100?

Heres the picture when I took it at a 1/100 shutter speed and that was the clearest shutter speed:

How can I make this picture any clearer with aperture? How do I change that?
I just got this camera and I don't know much about it

Use the sunny 16 rule.

1/ISO @ f/16

What you will want to do is shoot the moon at about f/8 which will put your shutter speed up to about 1/ISO + two stops faster @ f/8

You will need a lens that is at least 300 mm to make the moon look like more than a round white ball in the sky.

You are exposing for the light falling on the moon and that is exactly the same as what falls on the earth during the day. In fact, you may have to stop-down a little since there's no atmosphere on the moon to reflect any the light from the sun falling on it.

If you let the camera do the work, it will not get you what you want. You have to take some control of the process to get good moon shots.

Manual mode is the best way. Aperture really doesn't matter, the moon is a quarter million miles away. Depth of field is a moot point. Shutter speed is important. If you let the camera decide, it will usually try and use a long shutter speed, and the moon will be blown out. Shutter speed will be the same as daylight, or less. That part depends on how much of the moon is visible. A full moon will be close to daylight speed, a quarter moon will be 2-3 stops slower.

A tripod is the way to do this, and a cable release makes it even better.

200mm to 300mm / f/8 / ISO200 (ish) / around 1/200th of a second.

Manual mode. Adjust ISO, aperture, shutter speed, single shot, etc… Refer to instruction manual for details.

Added in an edit - f/8 is important to get deep depth of field as The Moon is full of craters and mountains and a large aperture with shallow depth of field won't have a deep enough depth of field. No tripod is required as The Moon is so bright we talking about hand-held, crisp shutter speeds here.

Thank you for martin and fhoto ace, i got so many knowledge here.