Si no quieres equivocarte otra vez, no lo hagas a tontas y a locas, planifícalo.If you don't want to get it wrong again, don't do it without thinking. Draw out a plan for it.
b.
Una frase idiomatica cuyo significado no es deducible si se traduce palabra por palabra.
No compres a tontas y a locas. Gástate el dinero en algo que necesites de verdad.Don't buy things just for the sake of it. Spend your money on something you really need.
Ofendes a la gente porque siempre hablas a tontas y a locas.You offend people because you always say the first thing that comes to your mind.