General start:
* Começar: This is the most common and versatile translation.
* Iniciar: This is more formal than "começar".
Start doing something:
* Começar a + verb: For example, "Começar a estudar" (to start studying).
* Iniciar + verb: For example, "Iniciar a viagem" (to start the journey).
Start a business/project:
* Iniciar: This is a more formal and professional term.
* Criar: This implies creating something new.
* Lançar: This means to launch or release something.
Other possibilities:
* Abordar: This means to approach or begin dealing with something.
* Dar início a: This is a more formal way of saying "to begin".
The best translation depends on the specific context and the desired level of formality.