For a creative set of Harvard students, fall brings a certain set of anxieties: midterms, papers—and finding the perfect Halloween costume.

Many students have been planning their costumes for weeks, and Harvard Square business owners say that there has been an increase in the number of people buying accessories for their costumes.

For Lisa M. Shichijo ’06 and her blockmates in Mather House, Halloween is always a challenge. Determined to top last year’s sailor costumes, the group spent hours this week searching for the accessories and fabrics they hope will turn them into the coolest partyers at this weekend’s numerous Halloween parties.

Shichijo and her friends have designed Eskimo costumes of fur-trimmed parka jackets, hand-made, fur-lined skirts, and fur wrist cuffs. The girls will also be handing out Klondike ice cream bars and Ice Breaker gum during their party-hopping.

“We’re carrying around little coolers instead of purses,” Shichijo said.

For Socrates R. Cruz ’06, Halloween has been on the horizon for months— Cruz has been growing a mustache for his Zorro costume this year in order to avoid his usual pencilled-on substitute.

Square business owners have noticed an increase in the number of creative shoppers this year.

“People are more into making their own costumes and putting it together themselves,” said Stephanie Cole, assistant manager at The Garage’s Hootenanny store, between helping members of a steady stream of Halloween shoppers.

Terri Christopher, the fashion buyer for both Newbury Comics and Hootenanny, said that the stores have bought more accessories and fewer packaged costumes than in previous years.

“We are a company of creative individuals and we support people who want to express their creativity and individuality,” Christopher said. “It makes it a lot more fun if people can pick and choose what they want.”

Christopher said that this year’s most popular items include Napoleon Dynamite costumes, “anything pirate-related,” sexy nurse costumes, school-girl outfits, police accessories, and wings.

One rule applies to almost every Halloween season, Christopher said: “People want to be either sexy or scary.”

At Mass. Ave.’s busy and crowded Oona’s, a popular second-hand store, owner Kathleen M. White dealt with the Halloween costume rush. She said it’s the 34th the store has seen. A seasoned Cambridge entrepreneur, White knew about the various costume-themed parties happening around campus this weekend.

One group of Harvard girls came into the store to pick out pimp gear to wear to Adams House’s Sweet ’N Nasty party, White said.

Many Harvard students will buy several costumes for various theme-parties they will attend over the weekend, she said.

But for the procrastinating Halloween partyer, prepared costumes are the preferred choice.

At Hootenanny, sexy cop and pirate costumes have been especially popular this year, Cole said.

At Oona’s, inexpensive feather masks are a popular last-minute choice, as are cat and bunny outfits.

More economically-minded students, however, seem to be recycling last year’s costumes by adding some extra flair. Tina M. Valverde ’06 is dressing up as Ursula from The Little Mermaid by combing out the hair from the wig she wore last year.

Candace “Cece” Keefe ’07 and her blockmates will not be purchasing anything for their Halloween costumes this year. Inspired by the recent release of the film “March of the Penguins,” the group will be dressing up as penguins, wearing black pants, shirts, and ski masks.

They plan to fashion beaks and webbed feet from orange construction paper and will use pillows and white poster board for their penguin stomachs.

For one Oona’s shopper, Ben D. Wei ’08, Halloween is merely a means to an end. Wei says he wants to look “classy” in his James Bond costume, complete with a tuxedo, a red bow tie, a silver gun and a full martini glass.

“I will be drinking all night,” he says.