Las prisas son malas consejeras

Las prisas son malas consejeras
 

In English?
It means that when we do sth in a hurry, we might make a mistake.

Haste makes waste

Esa traducción es mía:)

I can think of a couple of sayings which are in the right area but not quite the same:

Marry in haste, repent at leisure
More haste, less speed

Easy does it.

Another saying with the same idea
"Visteme despacio que tengo prisa"
Saludos :D

Slow and steady wins the race.