I do not consider myself a foremost authority in EFL instruction, but through my unique experiences from teaching foreign nationals that is almost close to a decade, I came to understand and realize that there are patterns to these pronunciation difficulties.
Aside from patterns, there are also simple and practical solutions to it without being too technical and would add on to the confusion or being too simple without understanding the intricacies of the underlying causes of these difficulties.
How then should we find the right balance in learning pronunciation in a practical and "easy-to-digest" manner, while at the same time making it insightful?
Here are some practical suggestions to your pronunciation woes:
1) If you encounter a word that is difficult to pronounce, "syllabicate".
a) pronounce the word slowly
b) listen to the beat of each syllable as if you're listening to music
c) each syllable corresponds to 1 beat
d) write down each syllable and tap the table or the back of your hand to each beat.
e) check the dictionary to confirm the main stress and proper vowel and consonant pronunciation
*** a syllable is a language unit that consists of the combination of consonant and vowel sounds
ex: demonstration: de-mon-stra-tion (4 syllables)
simple phonetic representation: \deh-m'n-STREI-sh'n\
3rd syllable: Main Stress - the strongest sounding syllable in a word
2) Practice - once you have identified the number of syllables as well as the main stress of the word, you have to say it repeatedly - slow at first and making it faster as you become more comfortable with it.
3) Record your voice - since pronunciation is not just acquiring the "American accent", but also gaining more awareness and realizing if you made a mistake or not, recording your voice as you pronounce a word would be a valuable reference. You could make comparisons and make the necessary adjustments if there are still some inaccuracies. Moreover, the realization that you gain is essential during conversations. This means that you're more "connected" with the words that you're saying and how you say it. If you make a mistake, you should be able to detect it and correct it promptly - because you are now more "aware".
4) Observe - Enhancing your awareness is all about resourcefulness and creativity. When doing some pronunciation exercises, you can use a small mirror right in front of your face as you can observe closely how you open your mouth, the shape of your lips (rounded or unrounded - Vowel sounds) and to a certain extent, tongue position. Articulation of sounds depends on these elements as well as how your mouth "feels", whether "tense" or "relaxed" (vowel sounds). Observing your mouth, listening to yourself as well as processing these information that you gather is a very efficient way to establish an "active" connection between your mind, the words that you say and what actually happens inside your mouth when you pronounce different words.
5) Take it for a spin - Now that you have acquired what is necessary to improve your pronunciation, use it when having a conversation with your teachers or with friends who are also English learners. Nothing is more valuable than learning from experience. If you make a mistake, just correct it and try again. Teachers most especially, would gladly help you with your difficulties and "fine-tune" your learning strategies as well as give you more insightful tips to aid your learning.
I also have found a very specific study done by Michael Kistler and Joseph Sandkamp who presented useful information between the differences of Japanese "Katakana" English and the Standard American English.
The study is really meant for teachers, but I don't see the reason why students shouldn't have access to it. After all, as I have said in my other blog - we can all be teachers in our own right, because we are all students and we never stop learning.
I hope this would give you the necessary realization as well as empowerment that learning a foreign language shouldn't be too difficult to the point of feeling hopeless about it.
Keep the faith!