If you started learning Serbian and you are confused as to what might be the difference between DŽ and Đ sounds, let me help you by taking you through these five steps:
Which of these two sounds is softer to your ear ?
Dž/dž (or Џ џ in Cyrillic)
Đ / đ (or in Cyrillic script: Ђ ђ)?
Step 2: If you don't hear ANY difference, let me tell you that the sound Đ is much softer than DŽ.
*You'll get this sound to be softer, i.e. produce Đ, by pressing the tongue onto the lower teeth. Repeat "đ" several times and feel the tongue low, behind the teeth, touching them.
*To get the harsh "DŽ" curl your tongue behind the upper teeth, slightly above them. You'll notice that the sound becomes less soft as you raise your tongue upwards. (even curling it backwards). Now repeat it several times.
Step 3: Try to contrast the soft Đ with harsh DŽ, paying attention to the tongue position and listening to yourself. Can you hear the difference ?
Now it's time to practise with minimal pairs and not-so-minimal pairs, because there aren't that many words with Đ and DŽ: