"DON'T COUNT YOUR CHICKENS BEFORE THEY HATCH"
A very common idiom in English but might not be so well known here in Spain. Essentially this means that you should not make any plans until you have verified the positive outcome that you are looking for.
That might be a little confusing to understand so here is an example: "When I get promoted I am going to use the extra money to pay for an expensive holiday!"..... "Don't count your chickens before they hatch!!!" (The promotion this person is hoping for is not guaranteed so they should not plan too far in advance. Is there an equivalent in Spanish?
Hope that helps!
Soy el director de Daniel Smith + Partners. Tengo más de 10 años de experiencia enseñando inglés a españoles.