The sound of Qaaf has no equivalent in English, so to pronounce it you need to make a sound which comes from deep in the back of your throat. A sort of cross between the English letter, ‘q’ and the English letter, ‘k’.
To make the sound, move your tongue to the back of your throat as if you are trying to block your windpipe and say the sound 'aaagh' in a forceful way. Now add a 'q' to the front of 'aaagh' and make the sound 'Qaaf'. To make sure you have the correct sound try and find an Arabic friend to check your pronunciation.
Daniel McLaughlin in his Bradt guide to Yemen says,
“The letter qaaf is one of the landmarks of Arabic, in part due to its place in the world ‘Qur’an and in part due to the baffling reaction it presents in transliteration (how can there be a ‘q’ without a ‘u’ ~as in Qatar?~).
One author noted that writing using the 'q’ sans ‘u’ in transliterations made Arabic to reek of savagery. Moreover, English speakers simply didn’t know how to pronounce it. In classical Arabic, the qaaf was pronounced like a ‘k’ sound back in the throat, similar to the sound you would make when imitating a crow.
Making the sound takes some effort and a story relates that during the Sana’ani-Ta’izi war in Yemen the Iman of Sana’a would point to a cow [baqqarah] and ask those entering the city to tell him what it was. The Sann’anis would say ‘baggarah’ and were admitted entrance, whilst the Ta’izis gave themselves up by saying ‘bagharah’ were sent to the gallows.”
The differences are small between Qaaf and faa. They are both the same shape, but whereas faa has one dot on top, Qaaf has two dots on top. Also with Qaaf its tail goes below the line when writing the independent and final versions of the letter, like so:
NB. for a full explanation of why there are four versions of the letter Qaaf, click here
NB2. the pink colour indicates a connection with another letter, either before or after Qaaf.
Now see if you can find the letter Qaaf in the images below:
I love this sign: