The "ng" is hard for many students.
I teach it in two steps.
1 - English has 26 letters and 44 sounds. So, letter groups indicate sounds.
"n" is a sound, "g" is a second sound, and "ng" is a third sound (not "n" followed by "g").
2 - The following words help students hear and produce the sounds.
"ban" [bæn] - standard "n" [n] sound
"bag" [bæg] - standard "g" [g] sound
"back" [bæk] - standard "k" [k] sound
"bank" [bæŋk] - actually pronounced as "ba-ng-k"
"bang" [bæŋ] - standard "ng" [ŋ] sound - pronounced as "bank" without the "k"
Then we practice a few minimal pairs very slowly.
"kink"/"king"
"sink"/"sing"
"rink"/"ring"
"honk"/"Hong Kong"
Then we work on some common verb forms.
"running"
"eating"
"sleeping"
"working"
Students may have a residual short "g" sound. This is because the tongue position for "ng" is the same as for "g" and students incorrectly stop the nasal sound by closing the velar flap at the back of the mouth before moving the tongue to release air through the mouth. When the tongue moves away from the "g"/"ng" position first, there isn't a short "g" sound.