In my Amsterdam drawing classes I offer the possibility to learn creating portraits either from photos or from the live model.
Learning to draw from the live model is a demanding discipline, so it is perhaps a good idea to start by learning to draw faces from photos on the internet, since you can choose the level of difficulty and type of face, as well as enjoying a model that you can summon whenever you feel like and always stands still.
One of the cited methods to learning to draw the portrait is the Loomis Method. Andrew Loomis was an illustrator who could create faces and characters from his imagination thanks to the deep knowledge he had from the human skull and anatomy.
To illustrate the power of a method and knowledge of a subject, here are two portraits that I have created. This first one was created through pure practice and honing my powers of observation:
This was drawn from the live model during 3 sessions and it's a work of pencil on paper. As you can see, there is plenty of detail on this drawing, all the parts of the face seem to be in the right place, and there is knowledge of using the gray scale, called values, to achieve a sense of volume. However, from an academic perspective this is a fairly weak drawing as I will explain by pointing to the strengths of this next example.
This was done using academic knowledge and the Loomis Method:
You will argue the differences are small, but then again learning to draw is learning to understand the power that small details have on the whole. Notice the stronger knowledge of anatomy, which becomes apparent on the structure of the eyes, nose and lips. The skull structure is also well understood, which allows the values to more clearly show the different planes of the head. This all sounds almost too technical, but it gives the drawing a certain clarity of thought that the smooth and mooshy result of the previous one does not achieve.
Having a method and learning it through drawing classes also allows you to start doing the 'mechanical' part of the drawing in a more sure-footed way, and in turn focusing more of your attention on compositional touches and fancier expression. Notice the play of edges on the hair, which are sometimes diffuse and sometimes very hard or broken.
When learning to draw with a particular method, be aware that some of your first results will be even worse than the drawings you normally produce. This is OK, you're taking a step back in order to absorb the new method. Sometimes this feels terrible and its frustrating, because your eye is ahead of what your hands can do, and it's telling you the results are no good.
In this particular example, the first drawing though week bears a closer resemblance to the model, while in the second one, a good piece of art has been created, but resemblance has suffered, though not dramatically.
The Loomis Method focuses on thinking of the entire skull as a structure in space, with a very specific shape, which once grasped allows you to place the features in the correct position. This method proves something rather counter-intuitive for beginning artists, which is that the individual features can never help enhance resemblance when the correct structure of the skull has not been assessed correctly.
Stick with it and you will get there with method, practice and discipline. During my Amsterdam drawing classes I encourage students to only draw at a speed at which they can be accurate and not a second faster. Only frustration will come from rushing in and building on top of a shaky foundation.