What it means
The standard greeting, used at any time of day. It literally means "you good" — no verb needed.
When to use it
Works for strangers and friends alike. For people older than you or in a formal setting, 您好 (nín hǎo) is the more respectful form.
Examples
nǐ你hǎo好，hěn很gāo高xìng兴rèn认shi识nǐ你。
Hello, nice to meet you.
nǐ你hǎo好，qǐng请wèn问xǐ洗shǒu手jiān间zài在nǎ哪lǐ里？
Hello, where is the restroom?
lǎo老shī师nǐ你hǎo好！
Hello, teacher!
The full set of survival phrases for greetings, dining, shopping, and getting around, each with audio.