When used with animate nouns, the preposition для generally means 'for' in the sense of 'for the benefit of, for the sake of'. It is always used with the Genitive case.
It is sometimes difficult for the learner to tell whether to use the Dative case or для + Genitive, but one thing to bear in mind is that для always emphasizes good intentions.
Observe the following contrast: (1) is a simple statement, using the dative, but in (2) the Dative could not be used because the adverb специђльно so obviously emphasizes good intentions.
(1) Ї тебљ купќла ромђн. I bought you a novel.
(2) Ї ітот ромђн купќла специђльно для тебї. I bought this novel specially for you.
The phrase with для often occurs at the beginning of a sentence, a position into which you can put things for special emphasis; compare:
Ї емџ сдљлала перевћд. I did a translation for him.
Для негћ ї бы всё сдљлала. I'd do anything for him.
The rule of thumb is: don't over-use для; use Dative with people-nouns unless you want to emphasize the benefactive meaning, and use для with nouns not denoting people. The preposition для means 'for' in other senses as well: 'with respect to' and 'for the purpose of'.
Хћлодно для МосквІ. It's cold for Moscow.
Ї іто сдљлал для простотІ. I did that for simplicity (simplicity's sake).
Вћт дровђ для кострђ. Here's the firewood for the campfire.