The best way to keep your sensor clean I have found, is to only change the lens when the sensor is cold (not yet been turned on that day) and before you start shooting if possible, this way the sensor has no heat and therefore less static attraction, which I don't know if this is true, but it is what I do. If you need to change lenses in the field, then get back into your vehicle or get somewhere sheltered to change the lens if possible, so you are out of the wind, or rain, or sea spray etc, but let the sensor go cold for as long as possible before changing the lens if you can. Run the camera's cleaning vibrate function with the body/sensor vertically upright, so any dirt or specs drop down into the lower part of the body, rather than dropping into the back of your lens. When you do swap a lens at home and after mounting the new lens, hold the newly unmounted lens upright with the mount end facing down and give it a little shake to dislodge any particles and let them drop out of it before putting the mount cap back on. Also if I do this at home, I will use my blower to help dislodge any possibly attached particles between shakes of the newly unmounted lens.
This way I find I can avoid having to clean the sensor for quite some time, but when I do, I make sure the camera has been off for at least a day beforehand for the same reasons given above.
Once you have cleaned the sensor with a sensor swab and cleaning fluid etc, hold the camera vertical in front of a light and move the body around to see the shine or reflection of the sensor, to see if you have any liquid residue still on the sensor and clean it of with a second swab if you have. I also put any used wet used swabs back in their packet until I have finished the sensor cleaning, so I can give the front element of the lens a quick clean also.
Having cleaned the sensor and lens front element, then open the lens to its widest aperture and defocus, then take a photo of a white wall, load the file into PS and scan at 100% for any bits still left on the sensor, of which there will still be a few, especially near the outer corners, but if there are only a few, then leave it at that, but if they are big, then go through the whole process again after leaving the sensor to go completely cold again, which I know is tedious, but it is what I do.
Also it is a good idea to try and keep the same lens on all day, or only swap lenses when you really have to, so try to decide what what you are going to shoot before you set off out and put the correct lens on before you go, but take your other lenses with you just in case and if you do ave to change lenses, then do it as outlined above.
If you have a zoom lens and especially if it a pump action style zoom, then to dislodge all the crap you will get into the body of the lens over time, try putting some double sided sticky tape inside your lens cap and then mount it onto the lens mount loosely, then pump the lens vigorously several times. I have even heard of photographers using their hoover's suction hose held near to the lens's rear mount as they pump the zoom lens.
Having said all this, a few years ago I went on a grand tour right up the coast of Maine, and after the first day or two, I realised I had a dead bug stuck to my sensor (aren't they called noseeums or something in the US?) and no way of cleaning it off, as we were right out in the sticks and I had forgotten to take along my cleaning kit. Hey ho...