Finding pronunciation exercises should not be difficult as the Internet has a wealth of information, but you will need a headset with mouthpiece to record your voice. A good language software is also recommended as they assess speaking, and hence pronunciation, as part of their program.
Online tests focus on two things -- stress and intonation -- as the principle components of pronunciation. If letters are the building blocks of words, then stress and intonation are the foundations for good pronunciation.
Words and phrases are not expressed in a flat tone, and indeed, it's where the voice places its emphasis within a word that often determines whether it's understood or not.
Online practice exercises enable students to concentrate on the mastery of these skills.
After practicing and taking any online tests, you may wish to refer to a dictionary as a tool to explain word stress. Stress identifies which syllable(s) the voice should emphasize more when speaking than others and dictionaries identify the different syllables in a word by placing a break between each one.
For example, the words photo, photographic and photography all look very similar, but different syllables are emphasized in each of the words. See if you can identify which syllable is emphasized in each word.
Like word stress, intonation is incredibly important. Intonation is how the pattern or melody of one's voice changes in connected speech, and understanding when the voice should 'fall or rise' in tone when speaking words is exceptionally important.
When listening to a word, try to listen to how the tone rises or falls across the length of the word. It's often the emphasis that is placed on words that determines meaning, as the same word can be expressed with rising or falling intonation to express a question, or certain emotion.
The word 'really', can be expressed as an affirmation, an acknowledgment, but when expressed with steep rising intonation, it can be used to express shock, even horror about a particular event.
While not as readily available as dictionaries and online recordings, phonetic diagrams show how to use the mouth, tongue and teeth in pronunciation and are language specific. Different countries use their mouths in different ways when speaking, and what may be easy for one person to say, may be near impossible for another, simply because they don't use their mouth in such a way for their native language.
Practice how to use your mouth, tongue and teeth in the pronunciation of each letter of the alphabet for the language you intend to speak.