While many upperclassmen this time of year are preparing to either move back into their old bedrooms soon surrounded by junior-high memorabilia and high school sports trophies, others are enjoying their last few months of freedom before they start the nine-to-five grind. But a select few are already in business, calling the shots sometimes before they even graduate — and with any luck, they will turn a profit before the six-month grace period on their student loan payments expires.

Some of America’s most successful entrepreneurs began their business ventures before they were even legally allowed to discuss financing over a few cocktails, and with the help of successful college business programs and supportive personal networks, they have learned how to succeed.

THE RIGHT TIME FOR RISK

Joanna Alberti, a 2003 Boston University School of Management graduate, was working at Boston advertising agency Hill/Holiday when she considered seriously acting on a lifelong hobby.

Voted “Class Artist” in high school, Alberti had been making greeting cards with witty dialogue and iconic female silhouettes, which friends and co-workers suggested she market at stores after selling them at a Hill/Holiday charity craft show.

“It wasn’t really something I thought I’d do full time,” she said, because she already loved her advertising job. “I wanted to take the risk while still only a couple years out of college.”

Alberti spent close to a year developing her products while still working full-time, taking a grassroots approach by walking her product straight into the doors of countless stores and craft shows in hopes she could prove what she had was different than what they already had on their shelves.

In 2005, Beacon Hill gift shop The Flat of the Hill became the first store to carry her line, philoSophies, which features over 150 illustrated greeting cards and daily illustrations.

Now, customers can purchase philoSophies products on the website and at 56 stores nationwide, but they can still email Alberti specific descriptions of friends they would like caricatured on customized cards.

Now in its third year of business, philoSophies has grown too large to fit in the Boston apartment from which Alberti originally operated. So she recently moved back to her home in Rochester, N.Y., to accommodate the part-time staff who assist with production and packaging.

In March, she’s launching a line of cosmetic bags, tote bags, framed art, mugs, keychains and other gifts.

“All the effort you put in, it’s fun to see it come to fruition,” she said.

CO-EDS IN THE CONFERENCE ROOM

Babson College graduates Matt Lauzon, Jason Reuben and Cristina Acevedo had their custom jewelry design company up and running in August 2006, before entering their senior year. The company specializes in designing and delivering fine jewelry to customers’ specifications within 10 days of order placement.

Drawing on the Reuben family’s experience and expertise in the jewelry business, Lauzon and Reuben saw custom jewelry design as a vacant niche in the jewelry industry.

The two co-founded business club Invenio Group, as a place of peer support for business strategies, and were quickly joined by other aspiring entrepreneurs.

“A big part of it is acknowledging that you can’t be an expert on everything,” Lauzon said. “You have to ask for help and get advice.”

PUT YOUR MONEY WHERE YOUR MOUTH IS

Lauzon, Reuben and Acevedo began hashing out the details of their business with the help of other students. A generous Babson alumnus gave them $5,000 to help start Paragon Lake and Lauzon and Reuben each collected and contributed $25,000 of their own. After just over a year in business, Paragon Lake has partnerships with jewelers in eight states and Lauzon expects the number of company employees to triple by next year.

Michael Caslin, professor of social entrepreneurship and philanthropy at Babson, said that while other Babson students played sports, Lauzon and Reuben made research, networking and marketing their major extracurricular activities.

” It’s not [about] waiting for permission from anyone to try and make their business happen,” Caslin said.

For some young entrepreneurs, having a great idea and fervently pursuing it is the easy part – convincing others is the real challenge.

SMOOTH TALKERS

Cameron Mckenzie, a classmate of Lauzon’s at Babson and member of the Invenio Group, started his own marketing company, McKenzie and Associates, two months ago. The 22-year-old has struggled to make others take his ideas seriously, and says an entrepreneur’s confidence in himself and his business is his strongest asset when trying to market a company.

“When you’re going into meetings the first thing they notice about you is your age,” he said. “For them to take you seriously, you have to be composed and convey . . . that you know what you’re doing.”

Mckenzie has convinced more than a few people that he is a capable businessman — he now manages the website for online ticket retailer Alphatickets.com, as well as an online data backup company in Puerto Rico.

TEACHING THE ART

Entrepreneurship as an academic field is relatively new, and at many colleges courses are only offered at the graduate level. At BU, undergraduates can take elective entrepreneurship courses as part of degree programs in SMG.

This month, SMG’s online entrepreneurship program, which makes heavy use of networking, was ranked in the top five programs of its kind by Fortune Small Business magazine, said Elizabeth Nassar, director of SMG’s executive education programs.

Students in the online program come from all over the world and range in age from recent college graduates to entrepreneurs in their 40s and 50s that have already had experience running their own businesses. The flexibility of online “classroom” hours is a big draw, especially for business-owners or people with erratic schedules, like Trish Wadman, a 39-year-old mother of two.

With a bachelor’s degree in English literature and interests ranging from pottery to knitting, Wadman floundered for a while before settling on manufacturing homemade soaps and beauty products. The online program helped Wadman focus her vision for the company and outline concrete goals.

“You really have to understand your product and make sure that you have a clear direction of what your ultimate goal is,” Wadman said. “I think people are so excited about the idea they have and they don’t think about all of the elements that go into starting a business.”