One example of an approach you might take in translating can be seen in the answer to a question that a reader raised:
Question: When you're translating from one language to another, how do you decide which word to use? I'm asking because I saw recently in the Word of the Day that you translated llamativas as "bold," but that isn't one of the words listed when I looked up that word in the dictionary.
Answer: You must be referring to a translation of the sentence "¿La fórmula revolucionaria para obtener pestañas llamativas?" (taken from a Spanish-language Maybelline mascara ad) as "The revolutionary formula for getting bold eyelashes?" You'd probably be even more confused if I had stuck with my first draft, which used the word "thick," which you're unlikely to see anywhere else as a possible translation of llamativo.
I'll briefly explain the various philosophies of translation before discussing that particular word. In general, it can be said that there are two extreme approaches in the way one can translate from one language to another. The first is seeking a literal translation, sometimes known as formal equivalence, in which an attempt is made to translate using the words that correspond as exactly as possible in the two languages, allowing, of course, for the grammatical differences but without paying a great deal of attention to context. A second extreme is paraphrasing, sometimes called making a free or loose translation.
One problem with the first approach is that literal translations can be awkward. For example, it might be more "exact" to translate the Spanish obtener as "to obtain," but most of the time "to get" will do just as well and sounds less stuffy. An obvious problem with paraphrasing is that the translator may not accurately convey the intent of the speaker, especially where precision of language is required. So many of the best translations take a middle ground, sometimes known as dynamic equivalence — trying to convey the thoughts and intent behind the original as close as possible, veering from the literal where needed to do so.
In the sentence that led to your question, the adjective llamativo doesn't have an exact equivalent in English. It is derived from the verb llamar (sometimes translated as "to call"), so broadly speaking it refers to something that calls attention to itself. Dictionaries usually provide translations such as "gaudy," "showy," "brightly colored," "flashy" and "loud" (as in a loud tie). However, some of those translations have somewhat negative connotations — something certainly not intended by the writers of the ad. The others don't work well for describing eyelashes. My first translation was a paraphrase; mascara is designed to make eyelashes appear thicker and therefore more noticeable, so I went with "thick." After all, in English that's a common way to describe the kind of eyelashes that Maybelline customers would want. But upon reflection, that translation seemed terribly inadequate. This mascara, the ad pointed out, not only makes the eyelashes look thicker, but also longer and "exaggerated."
I considered alternative ways of expressing llamativas, but "attractive" seemed a bit too weak for an advertisement, "enhanced" seemed too formal, and "attention-getting" seemed to convey the thought behind the Spanish word in this context but didn't seem quite right for an ad. So I went with "bold." It seemed to me to do a good job of stating the purpose of the product and is also a short word with a positive connotation that might work well in an ad. (If I had wanted to go for an extremely loose interpretation, I might have tried, "What's the secret to having eyelashes people will notice?")
A different translator very well might have used a different word, and there very well could be words that would work better. But translation is often more art than science, and that can involve judgment and creativity at least as much as it does knowing the "right" words.