Probably already been said, but this era is my thing, so I'll add my suggestions anyway
for a day out you need comfort as well as glam, so
Shoes should be ballet pump type, I'd personally clash it, with bright green, or maybe blue flat pumps & a 3/4 sleeve cardi in the same colour - if thats too much for you, go for red, black if you must, but personally I think that will dull down a lovely dress
If its chilly, wear a pair of black leggings underneath, fishnet tights aren't good for a full days walking, they cut into your feet - flesh tights would be okay, but perhaps a bit slippery with ballet pumps
Handbag, red or black, if you need a bigger one, which is more useful on a day out, bucket shapes work well with a 50s look
Hair, scrape one side back/up & pin with a large flower - red would be good, or if you go with clashing cardi & shoes, green or blue
finish with big dark sunspecs (optimistic[grin ) look for retro shapes that suit you & bright strong red lipstick