Where the focus sits
The focus is the part of a sentence that carries the new or decisive information, the answer to the unspoken question. English usually marks it with stress where it stands (ANA paid) or with a construction like It was Ana who paid. Spanish relies more on position. You have three options.
Focus at the end
To highlight the subject, you usually move it to the end. The same words in a different order then answer a different question.
Two questions, two orders
¿Qué hizo Ana?
Ana pagó la cena.
Ana paid for dinner.
The action is the news.
¿Quién pagó la cena?
La pagó Ana.
ANA paid for it.
The person is the news, so she comes last.
The subject as news
Ha llamado tu hermana.
Your sister called.
Entirely new message, the subject comes last.
Esto lo arreglo yo.
I'll sort this out.
English stresses I; Spanish puts yo at the end.
Contrastive focus up front
You can also bring the focus forward. Then you contradict or single something out: this one and no other. What matters is what follows. If a pronoun picks the fronted element up again, it is just the topic you are talking about. If there is no pronoun, it is focus.
The blueprint
Topic or focus
With a pronoun = topic
Esa novela la leí en verano.
That novel I read in the summer.
Calm, no contrast. The news is en verano.
No pronoun = focus
Esa novela leí en verano, no la otra.
THAT novel is the one I read in the summer, not the other one.
Strong stress on esa novela.
Contradicting and correcting
A Lucía invitaron, no a mí.
It was Lucía they invited, not me.
Eso te dije yo, no lo contrario.
That is what I told you, not the opposite.
Vino tinto pedimos, no blanco.
It was red wine we ordered, not white.
Evaluating with poco, mucho, algo
Quantity words and eso are fronted especially often. Here the point is less contrast than emphasis and judgement. Again the verb follows directly, with no pronoun in between.
Poco me importa lo que piensen.
I couldn't care less what they think.
The neutral version would be No me importa mucho.
Algo habrá hecho.
He must have done something.
Bastante tengo ya con lo mío.
I've got enough on my plate already.
Eso mismo pensaba yo.
That's exactly what I was thinking.
