How to choose the best:
Fennel

Touch

The bulb at the base should be tight and firm, and the surface should feel crisp rather than leathery at all.

See

Look for a pale bulb giving way to brightly colored fronds at the ends of the stalks.

Smell

Fennel has one of the most distinct smells, so look out for a nice strong licorice aroma.

Some more details:

How to store

It's a good idea to keep your fennel in a moist environment while in the fridge to ensure that it'll last as long as possible. Wrapping the bulb in a moist towel or cloth definitely won't hurt here.

When it's in season

Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.