It depends on the expression, there are several ways. The literal translation of "each other" is "el uno al otro" So if you said "Mi hermano y yo nos miramos el uno al otro" (My brother and I look at each other) It'd be correct, but if you didn't add "el uno al otro" it would also be correct, and understandable, and natural "Mi hermano y yo nos miramos" (because of the usage of the reflexive pronoun "nos") It is only neccesary when you really need to clarify the meaning. If not, it's a bit redundant. Hope it helped!

Otra opción, mas formal: mutuamente. People help each other out. La gente se ayuda mutuamente.

Nos miramos uno a otro = We look each other. :). Have a nice day

Uno a otro

Hi!! at each other=el uno al otro :) 1) "We look at each other" = nos miramos el uno al otro. 2) "We like to smile at each other." =Nos gusta sonreirnos el uno al otro. 3) "We need to help each other and talk to each other." =necesitamos ayudarnos y hablarnos el uno al otro. I hope it'll be useful for you