its not that easy to explain but all forms have a certain flow and the idea is to simulate that when modeling.
example (its hand painted so dont laugh):
this are two balls connected. on the left you just outlined it and added the faces. the right one used the natural flow of the model (edge loops or meshflow).
and for everything organic this is a must to get good results. on top of that its neccessary for clean anims and it also saves faces because you only build the real shape of the model.
This method also ends in a clean mesh.
your mesh is going in the right direction but there are still some faces that criss cross arround the model.
you can check your meshflow by adding a checker mapping to it. the result should be clean and form the basic shape of the model by the map.
hope that helps
cheers and keep it up