I never intended to get into plamodels but kind of fell into it after accidentally buying some Gachapon figures that come with parts stuck in runners. I only have very basic tools but ended up buying an old HG of Dendrobium at a vintage shop which I've got to assemble now without ruining it too much, so I wanted to ask for pointers.

Is there some method to getting rid of nubs without leaving behind stressmarks that Im not aware of? I try cutting it away with the hobby knife and sanding it down with sanding sponges but it always leaves behind stressmarks. Is my knife not sharp enough and am I doing something wrong with the sanding?

Also, is there some trick to applying stickers? I put together this SD Gundam EX Standard kit of Nu-Gundam and it was hellish because I cant line them up properly.