Scented Geraniums: What to Do for Winter?

I purchased many plants from you in the spring, mostly herbs and scented geraniums. Geraniums purchased were: chocolate mint, mint, almond, balm. They have been in containers all season.
1/ They did not bloom, sun exposure was either morning or afternoon, got lots of water, fed with Miracle Grow every two weeks.

Scented geraniums are very high light plants. They can grow quite well in lower light situations, but to flower they need full sun. You might try to put them outside for the summer. But be careful not to burn them, since the foliage grown in lower light situations must be gradually hardened to take full sun. Take about two weeks to a month to move them from full shade to full sun. The earlier you start the less strong the sun will be to start with and the quicker the plants will adapt.
The other problem might be your fertilizer. If it is a high nitrogen fertilizer (the first number is the biggest, such as 20-10-10), you should switch to a high phosphate fertilizer (the middle number is biggest) to encourage flower production.
Also, scented geraniums tend to bloom only once per year, unlike the ivy geraniums and zonal geraniums. If you got them after their flowering period, they won't bloom again until next spring

2/ Do these plants need to be brought in for winter? Do they get cut back? Will they need water and sunlight or a cool dark spot in the basement?

If your winter temperatures drop to or below freezing, then the plants have to be overwintered indoors. You could cut them back, but leave any fairly drastic cutting for the spring to shortly before the plants start growing quickly again. they will need water and sunlight, but will need less of it if they are kept cool. Letting them dry out will kill them as will keeping them too wet while they are not growing much for lack of light. Keeping them too warm during low light conditions will have them grow weak and leggy growth that could sap so much strength from the plant that it never recovers. If you have too little sun, you might consider double light fluorescent light fixtures timed to stay on for about 14 hours per day.