Do you want to know how to build a good FEM model or what is the best FEM modelling technique? Actually this was also my question as i started using FEA program. Then i took some examples from the TPL (Test Problem Libraries) delivered with the FEA programs and follow their guidance about how to build "good" mesh (modelling) with the preprocessor regarding aspect ratio, angle of the element edges, and the shape of elements. This is all to avoid negative Jacobian or bad (wrong) element types in critical regions. So i encourage you to take the manual from your FEA program vendor and try to use it with some simple examples.
Good luck !