Google translate and some dictionary websites have phonemic spelling and some even pronounce the word. Other than that you can listen to various videos for pronunciations.

ask a native speaker

the main problems most foreigners have with English is pronouncing the "r". Some other common problems are words ending in "-er" and "-al". Compare your speaking of this sounds with native speakers from TV or something! Depending what your native language is, the specific sounds that are difficult for you to pronounce varies. I am a linguist so I'm sorry if this is very technical!