Everybody wants to be the golden intern who gets hired at the end of the summer. But turning an internship into a full-time role is no easy feat. Bestselling management author and CNBC contributor Suzy Welch says that simply excelling at the basics — showing up early, leaving late and getting to know everyone — won't cut it. "Job interviews are bad enough," she tells CNBC Make It, "but summer internships are like an interview that lasts two months." To turn your internship into a full-time job, Welch says there are three challenges you'll need to ace:

CNBC Contributor Suzy Welch

1. Bring something the company doesn't already have

According to Welch, introducing "a big idea, a critical skill or unique insight into a certain demo or trend" is one of the top ways to prove that you're worthy of permanent employment. "School is all about telling teachers what they already know," she says. "Employers want to know what they don't know." Welch says that bringing this ability to the table will make you indispensable. "Best case scenario, your value-add should make your employers worry that you might take your brain or skills to a competitor," putting you in the perfect position to become an "instant ask-back."

2. Focus on making the company better

Instead of exhausting yourself trying to impress the big bosses, Welch says you should focus on demonstrating how you can personally make the company better and more efficient. "Sure, make it clear that you'd welcome [a job offer]," she says. "But more than anything, all summer you should focus on making the company better, smarter, faster, more competitive." "Sheer ambition — that's about you, and it's the ultimate turn-off. So forget the politicking, and focus on teamwork and results."

3. Prove that you can represent the brand