Words with different vowel sounds:
* About: American (əˈbaʊt), British (əˈbaʊt) - often pronounced with a more open "a" sound in American English
* Tomato: American (təˈmeɪtoʊ), British (təˈmɑːtoʊ) - a "tomato" in British English sounds closer to "to-mah-to"
* Schedule: American (ˈskɛdʒuːl), British (ˈʃɛdjuːl) - the "sch" sound is more emphasized in British English
* Either: American (ˈiːðər), British (ˈaɪðər) - the "ei" sound is different
* Data: American (ˈdeɪtə), British (ˈdeɪtə) - the "a" sound is closer to "ay" in American English
* Aluminum: American (ˌæləˈmɪnəm), British (ˌæljuːˈmɪniəm) - "aluminum" is spelled with a "u" in British English
* Bath: American (bæθ), British (bɑːθ) - "bath" has a more open "a" sound in British English
* Class: American (klæs), British (klɑːs) - "class" has a more open "a" sound in British English
* Water: American (ˈwɔːtər), British (ˈwɔːtə) - "water" has a more drawn-out "r" sound in British English
* Herb: American (ɜːrb), British (hɜːb) - "herb" is pronounced with a silent "h" in British English
Words with different consonant sounds:
* Petrol: American (ˈɡæsəliːn), British (ˈpetrəl) - different word altogether
* Rubbish: American (ˈɡɑːrbɪdʒ), British (ˈrʌbɪʃ) - different word altogether
* Flat: American (ˈæpɑːrtmɛnt), British (flæt) - different word altogether
* Chips: American (ˈfreɪnz), British (tʃɪps) - different word altogether
* Tube: American (ˈsʌbweɪ), British (tjuːb) - different word altogether
* Autumn: American (ˈɔːtəm), British (ˈɔːtəm) - "autumn" is often pronounced with a shorter "u" sound in American English
* Trolley: American (ˈʃɑːpɪŋ kɑːrt), British (ˈtrɒli) - different word altogether
* Zebra: American (ˈziːbrə), British (ˈzebrə) - "zebra" is often pronounced with a more distinct "z" sound in British English
This is just a small sample, and there are many other words that are pronounced differently. The best way to learn the differences is to listen to native speakers and practice your pronunciation.