I used the transfer decal method extensively for ICs/pads along with fine tip water resistant markers for traces. The trick that helped me a lot in avoiding err

I used the transfer decal method extensively for ICs/pads along with fine tip water resistant markers for traces. The trick that helped me a lot in avoiding errors was to redraw the circuit mirrored before writing it on the pcb, that is, with ICs having pin 1 on the upper right instead on the upper left. With time I learned to think the circuit mirrored and routed, so all my diagrams were drawn on paper very close to how they would appear on the pcb. Of course I mean a bunch of TTL/CMOS ICs, or one-two LSI max, and some transistors. Anything more complex would have been a nightmare to make this way, at least for me. Edit: The transparent sheets with pcb traces transfered on them are called "acetate sheets", made of the same material used in transparency projectors slides. They're used to transfer the drawing onto copper boards previously treated with photosensitive material via exposition to UV light, then the boards can be etched by the usual FeCl solution.