This is probably the hardest skill to learn without the use of a teacher .
The ANAC descriptor for Level 5 pronunciation is as follows
Pronunciation, stress, rhythm, and intonation, though influenced by the first language or regional variation, rarely interfere with ease of understanding.
Spoken English contains various sounds that are uncommon or even non-existant in Brazilian portuguese.
But, fortunately, tone of voice is often the same in English. For example, when we make a question in English, the pitch of our voice will often rise at the end the sentence.
Think about how you use your voice when you say the following sentences in portuguese
A aeronave está aqui. (fato)
A aeronave está aqui? (interogativo)