How to pronounce [d]/[t] in Chinese Pinyin

How to pronounce [d]:

Make an obstacle by keeping your tip of
tongue touch the upper alveolar ridge, compress air in your mouth and then release
the airflow by quickly break through the obstacle without vibration of the
cord. The sound of [d] is similar to the “d” in the English word “down”.

How to pronounce [t]:

The position of articulation is the same as
that of [d] but airflow is pushed out forcibly from mouth without vibration of
the cord. The sound of [t] is similar to the “t” in the English word “touch”.

The Similarities:

1. [d] [t] are alveolar plosive initials.

2. Vocal cord: [d] [t] are both voiceless.

The Difference:

[d] is unaspirated while [t] is aspirated.