Abstract painting in it's purest form, in which the image has no direct reference to the real world, has it's own challenges. Composition possibly becomes even more important in an abstract painting, as achieving an effective relationship between colours, values and shapes are often the essential aim.
Lessons on Abstract Oil Painting
If abstract painting is a particular interest then the sequence of lessons are a little different in that composition, including colour relationships is most definitely given more emphasis earlier than it would be with other subjects.
A variety of possible techniques and approaches to abstract painting can be covered.