auf wiedersehen (pronounced like "owf vee-der-zay-hen")
* auf - "owf" (like "off" in English)
* wieder - "vee-der" (like "wee-der" in English, with a short "i" sound)
* sehen - "zay-hen" (like "zay-hen" in English, with a long "e" sound)
und (pronounced like "oont")
* und - "oont" (like "unt" in English, with a short "u" sound)
viel Glück (pronounced like "feel glek")
* viel - "feel" (like "feel" in English)
* Glück - "glek" (like "gleck" in English, with a short "u" sound)
Putting it together:
"owf vee-der-zay-hen oont feel glek"
Note: German pronunciation can be tricky for English speakers, but with practice you'll get it!