There's so many styles and trends to pick from, she says.
Traditionally, women have gone for the full skirt with plenty of petticoats, flat shoes and little cardigans — the "good girl" look of the 1950s. But the Beach Hop festival with its classic cars span many decades so options are abundant and range from 1940s-1970s, Alena says.
Alena has seen the Warm Up Party evolve in past years. Girls and women often dress up in the rock and roll genre or its edgier rockabilly style with pencil skirts and leather jackets.
"There's the good/bad girl thing, you have your Sandra Dees and then you have Pink Ladies. But there's also the 1970s which is more your bohemian fashion."
Alena advises people to go for it.
"Go for the total look really, I can't wait to see you all."
The other judges are Simon Elson and Margaret Maclaurin. They'll be looking for best dressed man and woman, girl and boy and a family/group prize - prizes include a $200 voucher from La Diva, prize packs from Paper Plus and $200 Waihi dollars.