My technique is to just call every variable Temp1, Temp2, TestBit7 etc. That communicates to the people following that this was a half assed project done in a few hours before commissioning date, which couldn't be moved even though civil, mech and elec were all weeks behind. That way they'll completely understand your shortcomings, even if they can't understand your code.
Use inappropriate programming techniques to show people you can bend any code to your will, because flexibility is weakness. Using a single state machine for controlling multiple interdependent processes is a great technique. Refuse to use DFBs / AOIs, because you didn't need them in 1995, so why do you need them now?
Always buy the cheapest, least functional controller. A Zelio Smart relay is perfect for running a continuous process plant. Use 95% of the memory so any future additions need to follow your spartan resource allocation techniques.