Place the pot and plant into a clear plastic bag, inflate it and seal the bag tightly creating a miniature greenhouse for the plant. Put it in a bright but not sunny location, check it weekly to see that it has not dried out and within a few weeks roots will have developed and the plant will start growing once again. Gradually open the bag for a few days or a week to let the plant become accustomed to the room conditions and then move it to where your other plants are kept. You can follow the same procedure with a sucker you have removed from a plant.
There are many soil mix formulas. Because I wick all my plants I use a very light mix of one part potting soil or peat moss, one part coarse vermiculite and one part coarse perlite. My wicking is 4 ply acrylic worsted yarn which I scour to remove any sizing and keep it wet when I use it. I use all 4 plys for a standard plant and split it into 2 plys for my miniatures and semiminiatures. I also use squat pots for my violets because they have shallow root systems. Squat pots are also called azalea pots.