How to Clean Dust from a Digital Camera Sensor
First, make sure the sensor is dirty. Simply set the aperture of the lens to the smallest size possible by your lens, often f/16, f/22, f/32 or even f/64 with a teleconverter attached (the smaller the better), and then take a picture of a white wall. The picture will show all the dirt on the sensor. Bear in mind that the image is reversed on the sensor, so dirt on the bottom of the picture is actually on the top of the sensor, and so on...
There are several methods to clean dust off the sensor of a digital camera. One excellent way is to simply hire a professional in a local camera store to do it.
One technique is to use a blower, but this will blow the dust into the shutter mechanism so not recommended. Blowers are good for cleaning the front element of a lens.
Another excellent way to clean a sensor is with a piece of tape, but not just any tape. It must not be so sticky that there is a risk of leaving residue on the sensor. One tape that comes highly recommended for not leaving residue is Duck Invisible Tape Matte Finish. Yes, these are the same people who make the Duck Tape confused with duct tape. DO NOT USE DUCT TAPE! DO NOT USE PACKING TAPE!
Use a Q-Tip to very carefully stick the tape to the sensor. Care must be given to not damage the IBIS (if applicable). Also, a Q-Tip is not necessary as it works well just to let the tape fall on the sensor without applying any pressure — try this first.
Pull the tape up and watch it lift all the dust off the sensor. Notice that this tape does not stick very well. This is what is so desirable about it for this application. Throw away the piece of tape after each use. It is possible to leave some tape residue behind from the edges of the tape. Simple re-apply the tape to pick-up this residue that was left behind.
To see all the dirt on the sensor, try a jeweler's loupe or a jeweler's clip-on loupe. It makes cleaning the sensor a whole lot easier because there may be miniscule particles not readily visible by the naked-eye.