Online tutorials address literally to everyone watching. But here’s the point: all voices are different from one another, and even if apparently there are common issues to handle, the reasons behind those issues are often different and even opposite from singer to singer. I.E. not hitting high notes, could be due either to an improper breathing management, or an excessive abdominal pushing, as well as to a poor posture or vocal hypertonicity. That means that – even if some vocal issues look similar – the causes varie from case to case and must be assessed by an expert and addressed in the proper way; a generic advice might be spot-on for someone, but counterproductive or even potentially harmful for someone else instead. A vocal coach must be able to assess YOUR peculiar characteristics and prepare a precise and concrete path for YOUR voice.
In brief, among all the information out there, what you might need is a tutor, someone who leads you through the discover of your voice day after day, who is accountable on results and on the strategy to reach them. This is something that no tutorial will ever offer you.