Techniques

Circuit board techniques

Toner transfer, Press-and-Peel(tm), photoresist, Sharpie, nail polish.

Ferric chloride vs. ammonium persulfate. How to dispose of etchant.

Commercial PCB fabrication. Vendors.

Construction techniques

Dead bug style. Manhattan style. Veroboard. Perfboard and point-to-point. Solderless protoboard.