On Marissa Mayer's first day in the big chair at Yahoo, she has to figure out which problem to tackle first to right a company that has been buffeted by scandal, financial trouble and, possibly worst of all, growing market invisibility.

"On Mayer's first day, she should be meeting with her direct staff and addressing the Yahoo troops," said Patrick Moorhead, an analyst with Moor Insights & Strategy. "She needs to get employees excited and provide some timetables for when her new team will execute to any new deliverables, like a new vision and strategy."

Yahoo announced late Monday that 37-year-old Mayer, a top-line executive at Google, was starting as the company's CEO on Tuesday. She is Yahoo's third CEO in less than a year, and industry analysts agree she has a huge job ahead of her.

Mayer herself announced on Twitter on Monday that leading Yahoo won't be her only new job. She is pregnant and due in October.

"Mayer has a successful track record and reputation for being able to plan and execute to what end users want, which is exactly what Yahoo has lacked for so long," Moorhead said. "But Mayer has no experience as a CEO, and she needs to be aware of potential blind spots. Great product people don't always make great CEOs and she needs a plan to get a few, quick wins under her belt."

So what should be Mayer's biggest goals in her new job? Analysts agree there are a few specific goals that she needs to achieve.

First, work on employee and investor morale.

"Both groups need to have confidence in her and her leadership," said Dan Olds, an analyst with The Gabriel Consulting Group. Added Rob Enderle, an analyst with the Enderle Group, "People need to believe Yahoo can be saved."

Part of improving morale, both inside and outside of the company, will mean laying out her vision for Yahoo and how it can climb back to the top again.

"Mayer needs to first establish an inspiring yet believable vision that clearly articulates what business Yahoo is in and why they will win," Moorhead said. "Then she needs to do a roll call to see who on her executive staff is in and who needs to be shown the door."

Mayer was Google's 20th hire and the company's first female engineer. In her 13 years at Google, which comprised most of her career, she rose to become a top executive who lead the company's critical Location and Local Services group.

She also was a public face for Google, giving interviews and speaking to enthusiastic crowds at Google conferences and industry events.

Olds said Mayer's experience makes her the right person to take over control of Yahoo.