For much of the year, houseplants are second-class citizens. They're shuffled around, moved outside for their allotment of fresh air and sunshine (like convicts in a prison yard), or, if left inside, they're overshadowed by the sexier outdoor garden which commands attention with its changing colors, peaking perennials, and vegetable harvests.
In my house they are even crowded on poorly lit window ledges to make room for our Christmas tree because the only location that can accommodate the tree happens to be the best window for the plants. So which member of the plant kingdom gets priority? The dead conifer, of course!

(The houseplant classic: spider plants!)
But when the garden enters hibernation and the Christmas tree is being ground into wood chips, it's the houseplants that are still colorful, still verdant, still recharging me by bringing life and lushness to the surroundings. So it's time I show the houseplants some love. That doesn't necessarily mean pampering because most houseplants are unfussy to begin with (especially mine or else they'll die quickly). What they really need is some interested attention.

(Night-blooming cereus with overwintering coleus and my aloe in the background.)
In the months of low daylight, abundant water and fertilizer will only confuse or even damage houseplants by contradicting their natural tendency to slow their growth. Houseplants are tender perennials and they respond to seasonal changes just like their outdoor brethren. Rather than flood them or push them into artificial growth spurts, it's best to monitor houseplants and water them thoroughly only when they're certifiably dry. If you stick you finger into the dirt and it's dry to your first knuckle, it's time to water. Let the water soak through until it's pooling in the tray (you've gotta have trays and pots with drainage!). Then let the plant be until it passes the dryness test again.

(The largest of my three purple passion plants, with my Christmas cactus. Pardon those dead leaves.)
That time period varies, however, since heat in our houses can cause houseplants to dry out faster than during the summer months. That's why these plants need attention--are they remaining moist in a dim corner, or are they baking near a heat vent? Either way they'll probably survive as long as you're aware of their conditions and take appropriate steps to care for them.

(Tillandsias, my new favorite plants. I run these under the faucet once every week or two, but that's another post)
A great way to know if your houseplants are happy is simply to touch them. Do they feel floppy? You're probably overwatering. Crispy? They're likely dried out. If the leaves of your jade plant are mushy then it needs water. If the Christmas cactus is drooping, give it more light and less water. None of this is hardcore botany, just a careful eye and caring touch. Just show them some love!