The phonetic transcription of ظ in Modern Standard Arabic is [ðˤ]. The ð represents the typical sound of TH in words like 'the', 'this', 'brother', etc. (Remark: it is different than θ, the sound of TH in words like 'theater' or 'mathematics'). The small ˤ represents Pharyngealization, also noun as Emphatization (because ظ is an Emphatic consonant). It means that the sound comes from deeper in your throat, and the sound is also supposed to be deep and low. Of course, I just explained the sound theoretically, and it requires lots of practice before being able to produce it naturally in a conversation, but that's up to you.
N.B.: I tried to explain the sound ظ in Modern Standard Arabic. In most dialects, this sound has changed (either to a [dˤ] or a [zˤ]).
Once a native speaker explained it me in this way, because I had the same trouble like you. ;-)
Go on Google Translate and exercise it with the word Abu Dhabi
. Tip of the tongue goes a bit out of the mouth like in th.
. Put the tongue only against the upper teeth and keep the teeth a little bit open.
. Now you have to elaborate the back of your tongue for producing the deeper sound.
Have fun. ;-)