Pronunciation includes features of language and skills. The language is. included in
vocabulary and grammar and the skills are combined between speaking and listening.
We pronounce by noticing and understanding rules and patterns which lie beneath the
surface of speech like vocabulary and grammar.
Because pronunciation is part of speaking, it is also physical. To pronounce a new
language, we need to re-train the muscles we use to speak.
And pronunciation involves listening to how the language sounds. We can practise by
focusing on connected speech.
In pronunciation, our tongue, lips and jaw (vocal articulators) physically shape our
pronunciation. When we learn our first language, we develop speech habits which we
may not be conscious of developing. This is what makes pronunciation in a new
language so difficult – we carry with us the speech habits from our first language.
However, an accent is not a problem. You can keep your accent and still be understood.
A learner's aim may be to communicate with other people from around the globe. With
this in mind, you should focus more on aspects of pronunciation which aid
understanding.
Some features of pronunciation make the message clearer to the listener. For example,
a clear difference between the /r/ and /l/ sounds.
You can teach or practise intelligibility with communication activities. Using the /r/ and /l/
example, you can put pairs of words such as correct and collect into a game in which
success depends on the learner being able to hear and say the difference.
You can teach optional features of pronunciation to make words easier to say, such as
saying gonna instead of going to. Gonna may be easier for a learner to say, and is
closer to how many native speakers pronounce going to. However, it is optional
because most listeners will understand gonna or going to. 
Notice what your lips, tongue, jaw and throat muscles are doing when you speak, in
your own language and in English.

For example, when you say the sound /t/, pay attention to the tip of your tongue. Does it
touch the back of your teeth, or the ridge above them? How is it similar to the /d/ sound?
How is it different?
Become aware of your beliefs and prejudices about pronunciation.
Many speakers of English say that they never use glottal stops (the sound we make
when we close the glottis while speaking), but they do. According to John Wells in
the Longman Pronunciation Dictionary, most people use the glottal stop to replace the
/t/ sound in words like button.
Deciding to learn English with a British or American accent is not a helpful target.
Instead, focus on features of pronunciation which could distort your message. For
example, speakers of Vietnamese may miss consonants from the ends of words, and
speakers of German may confuse the /v/ and /w/ sounds. This might make it difficult for
listeners to understand some words. 
The most serious pronunciation issues are the ones we are not aware of.
For example, people who speak Spanish already make sounds which resemble the
English /b/ and /v/. However, in Spanish, /b/ and /v/ are allophones – variants of the
same sound.
Spanish hearers may not notice the difference, because hearing a language – like
speaking it – is a habit we form in childhood. If a difference is not significant in our
mother tongue, we might not notice it in the language we are learning.
Teachers need to help learners to notice such features in the target language. We can
do that by teaching a short rhyme which includes many examples of a sound, so that it
becomes noticeable to the learner.
English spelling is unhelpful for learners. It evolved out of speech, but then speech and
spelling went their separate ways. Consequently, there are often many ways of spelling
the same sequence of sounds.
Conversely, the same sequence of letters may be pronounced differently, resulting in
homographs like row (line) and row (argument).
Homophones and homographs are challenging for learners of English, but they aren’t
the main problem. They are extreme cases of a bigger issue – the irregular relationship
between English spelling and sound across the language.

It’s almost enough to drive a learner to despair, and we teachers don’t help much by
throwing a lot of –ough words at the class while suggesting that there is no rhyme or
reason in English spelling. In fact, there are actually many patterns and regularities.