Try to knead marzipan/almond paste and sugarpaste without using any icing sugar. This will prevent the paste becoming too dry and cracking or crazing around the top edges when applied to the cake.
Use Icing sugar liberally to prevent sticking to the work surface while rolling out - the last thing you want is for it to stick at this stage.
Be very sparing with icing sugar on the top of the paste.
Use a light dusting of icing sugar to allow the EDGER to glide smoothly and easily.