Wee tip I picked up that works well is using marker pens to put down a block flat colour and then using pencils on top to create depth, texture and shadows. White gel pen for a few minor touches to lift it.
Top tip: do a quick test with the colours you are using because depending on the brand sometimes funny things happen and you end up with colours you didn't expect.
I got a lot of tips from Youtuber
Sarah Clarke* and did a copy of her white frosted cake in alcohol pen and markers. It's not finished and still needs some candles put on the top but I'll get round to it one day. Oh and and I winged the shadow in the bottom and it was a huge mistaaaaake!! that I couldn't properly fix but hey ho! The technique worked well even in my ham fist
*she specialises in adult colouring books and has loads of great videos about techniques and things to try.
I bought a set of 48 Arteza pencils and 48 Ohuhu markers on sale and that's what I used in the cake pic - they are super pretty!
I did have a set of cheap Staedtler pencils but I couldn't seem to get many layers down before the colour was saturated but not vivid, if that makes sense?
Come on peeps share some more pics