Some user tips to help Siri better understand what is said are to use the built-in features, such as the Edit option to correct mistakes. Speaking slowly and clearly can also help.
If Siri misunderstands one or more words in a command or question, using the Tap to Edit feature corrects Siri's translation of the phrase. Siri provide results based on the corrections and remembers them for future reference. If Siri mispronounces your name or the name of one of a contacts, saying, "That's not how you pronounce that name" prompts Siri to ask for the correct pronunciation. Siri provides the user with three options to choose from and remembers the one selected.
Siri can also learn about the phone user's relationship to his contacts. For example, if the phone owner tells Siri, "Call my wife," Siri asks who his wife is and remembers your answer for the next time the command is given.
Some users prefer the Raise to Speak option and feel that they get more accurate translation when using it. This option activates Siri when the phone is held up to the ear rather than having the Home button pushed. Using this feature requires turning it on in the Settings menu.