Here is how I do it (combination of advice received from different sources).
1) Spotting the dust. I find a magnifier pretty useless. Much easier is to set the camera to f16 or f22, open the computer an load a clean blue screen (such as the Windows blue), hold the lens close to the screen, and shoot a frame while moving the camera a bit (to avoid recording dust spots on the screen). Load the shot into LR, lower exposure, and crank up the contrast and saturation. You will see any dust spot, even the slightest one. Of course, in order to know where the spots are on the sensor, you have to take into account that the photo is upside down and left-right reverse. Thus a spot that appears on the upper left side or the shot is on the lower right side of the sensor. (Apologies if this was obvious.)
I got this tip to locate spots from a professional cleaner and since then always used this methodology.
2) Mount the camera on a tripod. For the actual cleaning. mount the camera on a tripod. This means you have to hands free. Point the sensor to a good light source, so that you see what you are doing. This tip I got from a fellow forum member.
3) Start with the invisible dust brush. Remove the first dirt with the invisible dust brush (or something similar). Because you know where the big dirt spots are you, you can focus on these areas.
This step is important because the worst thing that can happen when doing wet cleaning is that you still have a hard dust particle on the sensor because the swap will then push the hard particle over the sensor glass, and this may result in a scratch.
4) Check the result and repeat steps 1)-3) so until only fairly small spots are visible and then do the wet cleaning, using each side of the sensor swap only once.
5) Check the result and, if necessary, repeat the wet cleaning, using a new swap.
6) Don't let perfect be the enemy of the good. A perfectly clean sensor is almost impossible to achieve, and, unless you don't change lenses, will anyway last for a shot time only. So you know when to stop
.
BTW, if cleaning an M9 sensor sounds scary, wait until you get to clean a S2 sensor, the price of which is almost that of the M9P. However, after you have done it a few times, you get used to it.