Pronunciation is often a difficult thing for learners of a second (or third or fourth) language. This website will show you exactly what your mouth should be doing in order to make specific sounds in English. It also gives you example words so that you can hear the sound in the beginning, middle, or end of a word.
You can look up both consonants and vowels. This is great practice to reduce your accent. For added benefit, it is best to record yourself making these sounds to hear your progress.