I may be able to draw but colouring instead has never really been my thing - actually I've always been quite bad at it. But yesterday I purchased this pack of markers called Letraset ProMarker Set 1 and they are simply great, comparing to any other kind of markers I tried before, both on the act of colouring (no smudges etc.) and the final result... so I think they are going to be my default hand-colouring choice from now onwards (apart from the usual digital colouring with Photoshop or GIMP which I'm not using very often recently anyway).
Here you can see an example. Clearly I'm bad at colouring the same, but if you compare it with this previous drawing I think the difference is evident.