ooo well, for perspective and angles, 3d model apps are very helpful but don’t trace on the models unless you’re just practicing because tracing can really affect your artstyle and creativity. don’t be afraid to go all out when experimenting with colours to find your right palette. choosing the right brushes are important too because trust me, they really do affect your style. for shadows, dont use plain black, instead use dark/ashy shades of blue or purple. when rendering, dont smudge/blur out everything, only certain soft parts will do. pinterest is a great place for references. dont forget to learn color theory as well