What are the teaching methods to teach good three-dimensional geometry

Stereo geometry is the focus of high school mathematics and one of the difficulties, said it is the focus because stereo geometry is an important part of mathematics teaching, is a professional knowledge that students must master, said it is difficult to stereo geometry itself by the characteristics of the decision. Many students mention three-dimensional geometry will "talk about tiger color change", teachers also generally believe that three-dimensional geometry teaching is a thankless task, teachers think it is difficult to teach, students think it is difficult to learn. The author combined with teaching practice, the teaching of three-dimensional geometry to put forward some of their own views.