Both the articles I referenced in this document play the role of tutorials that introduce some feature extraction (FE) approaches based on signal energy and zero-crossing rates (ZCRs). They offer cutting-edge algorithms in which the feasibility of a balance among creativity, simplicity, and accuracy constitutes the main motivation. The theory presented, smoothly shown and accompanied by numerical examples, is complemented with source-codes in C/C++ programming language and interesting applications on neurophysiological signal processing, speech processing and image processing.