I will start this post with a disclaimer: I am not a professional couch cleaner or an expert on microfiber. I am an owner of a 10-year-old second-hand microfiber couch and I have tried and succeeded at keeping my couch looking relatively new by using this particular cleaning method.
First of all, for over-all cleaning of my cushions and pillows, I have the luxury of unzipping the padding from the covers and throwing them in the washer and then hang them to air dry.
I hang them on clothes hangers to dry. They look almost like new afterward.
I understand that some are not able to do that with their cushions and that you require another method of cleaning which tends to leave water spots. This is how I deal with that.
Here is a spot in the middle of the ottoman.
I use a damp rag with a bit of dish soap on it and scrub the spot.
Next I come in with my trusty shoe shining brush — I know that this sounds weird but this is what I use and it works. I brush the wet spots aggressively every 5-7 minutes until it completely dries. This seems to "feather" out the wet spot enough that it doesn't leave a water mark.
I use this same approach on the arms of the loveseat.
I use that same shoe shining brush to brush my couch every day to make it look neat and have nice lines on it.
Like I said at the beginning of this post, this is what has worked for me — this already-old couch has continued to serve my family well!