Accurate pronunciation and etiquette complement one another. A reader might follow the proper order of istiʿadhah and basmalah yet still mispronounce their letters. Conversely, someone may articulate letters correctly but not know the special practice at a surah opening.
Rights of the wording: proper consonants, vowels, shaddah, sukun and required qualities.
Etiquette of beginning: istiʿadhah and basmalah as appropriate to the situation.
Practice: recite a short surah slowly. Check the opening sequence separately from the pronunciation of its first few words.