Speaking of bathroom, that is one of the places to cut down on dust. Back in my film days when I developed film, I'd run the hot shower with the door closed for a bit to get some steam in the air. The steam and moisture would settle all of the dust in the air and keep it off of my hanging strips of film that I was drying.
If you have a large enough bathroom that you can use, you can do the same thing while taking pictures. It works pretty well. If you don't have a big bathroom you can also try getting one of those humidifiers that parents put in their kids room to keep the air most. Pick the smallest room you have that's big enough to put up your light tent and let it run for awhile. Also, keep a lint free cloth on your reflective surface until you are ready to shoot and put it back over it between shooting. that will help keep the dirt spots down.
Oh and learn to do dust spotting or get one of the ad-ons that will dust spot automatically cause you won't get rid of all of them.
I shoot on a front surface mirror and run into this problem as well, no matter how much I try.
Or (and this is a trick you don't see very often) you can shoot on water. If you take a large cookie sheet (the kind with a raised wall not the flat kind), put a block cloth in it and then fill it up with water, it will look like a mirror if you do the lighting correctly. And no dust problem.