I have had luck in the past with wintering over geraniums, succulents, and Streptocarpella plants (thus reducing my Springtime Flower-Shopping bill), so here I will tell you how I do it. It's somewhat a game of chance, but I think that's pretty much a given when one is working with plants.
I have found that most succulents are very easy to propagate. Perhaps since they come from unforgiving territory and they have a greater will and method of surviving. (sure plants have a will. Haven't you read The Secret Life of Plants?)
Here is an example of what my succulents do by the end of the summertime:
It's really as simple as snipping off a piece of plant that looks good to you, pulling off the leaves on the part that will be going in the dirt, and sticking it in the dirt. Done.
Here's a few pots that I have done and are ready for wintering over at home. I did move them into my sunporch rather than outside, so as to help them not to be overly stressed by the cooler nights outside during this transition phase.
This is my little "Colorado Pot"...because those rocks are from CO!
Geraniums tend to be a more trial and error sort of thing. Two falls ago, I rescued my MIL's hanging geraniums that she was going to throw out . I cut them back to about 3 inches high (making sure to leave some of the "knobs" where the leaves grow from and some leaves) and put them on a shelf in our cool unfinished basement. They started to grow some wimpy leaves by springtime, which I figured was a good sign they were alive. A few weeks to a month before it was safe to put them outside, I put them on my sunporch where they could get sunlight (yet not be shocked by direct sun) and be protected from freezing overnight. Then I put them outside and stuck a few of those fertilizer sticks in the dirt of each pot and was good to go for the summer. I did this for two summers with the same plants! This fall, though, I think it is finally time for the original plants to retire. But that is ok, since I have other plants I propagated off of them!
Which brings me to the other method of propagating Geraniums.
One way to do it is to cut off a geranium stem below a "knob", leaving enough stem to go into the dirt and enough to give you a plant above the dirt, pulling off all the leaves that will be going into the dirt, and putting this into water for a few weeks until you get roots and then plant them.
But I get impatient. Last year, an acquaintance was getting rid of a lot of her pots (and potting soil) and I took advantage of the opportunity as an opportunity to try a different method. All I did was cut off the geranium pieces, pull off the leaves, and stick them into wet soil. Some of them dampened off and died, but most of them grew and I even got blooms from these plants through the winter. So, this is how I am doing it again this year with most of my geraniums. I would suggest that you only have about 2-3" of plant above the soil, as the plants will get leggy by spring if they are much taller than that.
The Streptocarpella is one of my favorite plants. I believe it is a relative of the African Violet, and as such it does not like its leaves to get wet. It takes a little more care in watering than the other plants do, but the hummingbirds like it, and I love the purple flowers and the soft velvety leaves and hanging habit.
My method for propagating Streptocarpella is the same as for Geranium. Start with a pot with moist soil. Cut a piece of plant below a knob (this time, for a plant about 1-2" high above the dirt),
As with the succulents, I have my "new" Streptocarpella plant in the sunporch to offer more protection from the elements through this transition time.