Stinging nettles are an ideal wild food: They are ubiquitous, abundant, healthy, delicious, versatile and easy to identify. The young tender leaves at the top of the immature, pre-bloom plants make a lovely pot vegetable and a gorgeous green food dye for pastas, breads, cakes, icing etc.  A brew of either dried or fresh leaves can be enjoyed as a tea, made into a cordial, beer/wine, kombucha, or nettle-ade. The female flowers are like tiny green linseeds full of omega 3 fatty acids and all kinds of other goodness and can be dried or toasted or sprinkled raw on top of just about anything for a nutty and nutritious crunch.
Deadnettles, vaguely related to mint, are the closest lookalike to the stinging nettles, and, in spite of their grim name are merely without sting, not poisonous at all, and can also be eaten as salads and greens, so a confusion between the two families would only result in disappointment, not in accidental poisoning.

Older nettle leaves, after the plant blooms, are full of little granular crystals, so become unsuitable for use as a vegetable, but can still be used for teas and drinks.
I generally just harvest the top six leaves of young plants, the nettle tops, and then can use them twice: As a vegetable/food dye and, the blanching water, as tea or a basis for other drinks and soups.