This part, is rather delicate in detail, as I prefer to produce a good quality mesh.
Technically the modeling of the hairstyle is not complicated, all the difficulty lies in modelling creases and curves. It is thus a good exercise of modelling in itself.
Initially, you can guide yourself by working from the drawing of the head of face.
Create a rectangular face on top starting from Shape Rectangle, then add Mesh Eddit or you can collapse the stack into an Editable Mesh.
Using the top view, it is enough to initially extrude a edge towards the back of the head and then laterally like above.
Adjust the verticies to start to give the form to the beginning of the hairstyle.
Select the outer edges with Select Open Edges and make an extrusion with uniform Shift+Scale.
Adjust the verticies.
On the front of the head for the beginning of the mesh, it is enough to extrude in turn the edges like above. Make in the same the remainder of the edges but you can do all sets at one time.
At this stage one can apply Meshsmooth and adjust the general form with LPM cage.
Extrusions of the mesh.
The end finishes at a peak, for that use Collapse Edge.
Adjust the mesh well to give them 'nice' forms from every angle.
Select the others edges on around the nape of the neck and continue with Extrude Shif+Move.
With activated Meshsmooth, stop to adjust the verticies of LPM cage.