Below is a list of words that vary only by one having the beginning sound /t/ and the other the beginning sound /d/.
You can use this list to practise the sounds, or as a list of words to be careful in pronouncing.
Initial /t/ and /d/ are much easier to recognise than final /t/ and /d/. The mouth and tongue positions are very similar, but for /t/ we don’t use the vocal cords but instead release much more air, at times making it almost like spitting. You should be able to feel that air on a hand held just in front of your mouth.