Glossy iced biscuits - what's the trick?

[VenusInfers]

So I just love doing some of that there fancy icing on biscuits, a la Biscuiteers, but the icing often looks a bit dull, rather than the glorious gloss of my desire.

What AM I doing wrong? Help!

What colouring are you using? and how think are you making the icing?

I just use royal icing and it seems shiny enough

using sugarflair concentrated gel colours and packets of royal icing mix, so should be fine, theoretically... Sigh