Critique on heads

Hey guys i have been practising drawing the head from different angles using loomis' method and i'm having a hard time drawing the position where the head is looking up.
http://ji-sung.deviantart.com/art/Img-20170302-181202-666903432
http://ji-sung.deviantart.com/art/Img-20170302-181208-666904461
http://ji-sung.deviantart.com/art/Img-20170302-181234-666905687
http://ji-sung.deviantart.com/art/Img-20170302-181240-666905986
http://ji-sung.deviantart.com/art/Img-20170302-181248-666906350
http://ji-sung.deviantart.com/art/Img-20170302-182916-666906667
http://ji-sung.deviantart.com/art/Img-20170302-182934-666907043
http://ji-sung.deviantart.com/art/Img-20170302-182941-666907481

Up shots are always tricky. Here is a drawing from Burne Hogarths "Drawing the Human Head" that might
help.

make sure the eyes, nose and mouth follow the shape, or curve of the head. They're too flat which helps with making the drawings seem awkward

Hello, yes ibi is right the curve will help with the illusion of perspective, doing this technique is really hard i still have a lot of problems with it too! I also suggest shading, the shading will also help you distinguish the form of the head and fulfill the perspective.

Thank you all.