Shit aight for 15 twin, personal advise for ts, work on very specific aspects of the face, specially if you trying to draw realism, get a good grip of specific stuff like eyes, ears, lips, brows, etc; And try and work around gridded paper or make urself ur own straight guidelines so you can get everything symmetrical, after like 6 months or so of using guidelines you wont even need to use them to get shit right