List of hang-ups that I remember (not complete, as I've forgotten more than I remember):
No sport jackets/dress pants. Must be a 'suit'
No 'colored' shirts. Must be white (relaxed later, but still applied for Sunday speakers)
No bowties. Had to be standard. (later, younger brothers got in hot water for the 80s skinny ties)
Socks had to be worn (thanks Miami Vice)
No beards, of course, but mustaches had to meet Bethel standards. No 'soul patches'
No 'flaired' dress pants on stage (mid 70s as Disco came to power)
No 'short' over jackets in field service. Had to be 'full' length (think trench coat).
No necklaces or bracelets for brothers
No pants for sisters, not just in service or at KH, but anytime in public. Pants were for house work or gardening.
Sisters HAD to wear stockings/hose...no bare legs
No sundresses for sisters. Cover those shoulders at all times
No dresses/skirts above the knee
No slits in long skirts. (basically Sharia law on sisters if you think about it. Surprised they didn't assign burkas)
2 door cars highly discouraged. They gave talks chastising anyone who purchased a sports car over a family sedan that could be used in service
Unmarried brother and sister in same car - sister to ride in back seat.
Unmarried brother and sister at hall - if they sat beside each other more than two meetings in a row, then the congregation should expect a marriage announcement (that is paraphrased from a CO's talk on the subject, I shit you not)
Okay, that's enough... the more I think about it, the more I'm taken back to that time.