Spread newspaper over your work area if you're working inside. Allow yourself plenty of space. For example, the kitchen floor is a better choice than trying to work on the kitchen table. If you want to avoid messing up your house or laying down newspaper, work outside.
Tip your fern on its side on the newspaper. To loosen the soil, press gently on the sides of the pot if it is a plastic pot. For ceramic pots, roll the pot back and forth on the newspaper a few times to loosen the soil.
Gently tug on the fern and remove it from its old pot. If there is resistance, work your hand into the soil to the bottom of the pot to free any stubborn roots. You want to disturb the roots as little as possible, so ease the fern out as gently as possible.
Trim away any brown or broken foliage with a pair of scissors or garden clippers. Also trim away the lower foliage. This is the older foliage and removing it will improve the appearance of your fern. You can prune back ferns hard, but try to leave at least 1/4 of the central, younger fronds unless they are unhealthy.
Pour 1 inch of potting mix in the bottom of the new pot. Place the fern, roots down, on top of this layer. Add enough potting mix to fill in the pot, leaving 1/2 to 1 inch of space at the top. Water the fern well, but not so much that the potting mix is soggy.
Over the next two or three weeks, water your fern enough to keep the soil moist but not wet. Misting with a spray bottle also benefits your fern. Feed the fern weekly with a balanced liquid fertilizer or one specifically intended for indoor plants. By spring, your fern should show signs of new growth.