Tesla Motors (NASDAQ:TSLA) will report fourth-quarter results shortly after market close tomorrow. If the company's guidance for vehicles deliveries for the quarter holds true, this will be its biggest quarter ever -- by far. Furthermore, Tesla will provide its outlook for 2015. If you'll be tuning in to the report, here are some key figures and topics to keep an eye on.

Model S Red

Model S. Source: Tesla Motors.

Revenue and earnings: Analysts, on average, expect Tesla to report non-GAAP revenue and EPS of $1.23 billion and $0.31, up 62% and down 6% year over year, respectively. The decline in earnings signals Tesla's continued ramp-up in research and development spending as a percentage of revenue as it continues development of the Model X, plans the Gigafactory, and begins early work on the Model 3.

Gross profit margin: Tesla's gross profit margin has been soaring in the past few years as it maintains its high average selling price on the Model S and its manufacturing efficiencies and part costs improve. Tesla said in its Q3 letter to shareholders that it expected non-GAAP automotive gross margin to exceed 28% in late Q4. For the full quarter, look for an automotive gross profit margin on both a non-GAAP and GAAP basis of about 25% or higher, up from 23% and 22.6% in Q3, respectively.

Vehicle sales: Tesla guided for 11,180-plus vehicles in Q4, up 89% year over year and 44% sequentially. After exceeding its own quarterly guidance for vehicles for seven quarters in a row, hopefully Tesla can deliver again.

Full-year vehicle sales guidance: Based on previous comments from Tesla management, Tesla should provide guidance for 49,500-plus Model S vehicles in 2015, up about 50% from the 33,000 it guided for in 2014. The Model X is the big mystery. All we know now is that Tesla said it expects to begin delivering the crossover in Q3 and it said the production ramp-up will be faster than it was for Model S. For reference, during the first two quarters of Model S availability, Tesla sold about 2,700 vehicles.

Model X

Model S (left) and prototype of Model X. Source: Tesla Motors.

Demand: Since the launch of the Model S, Tesla's global demand has been well ahead of its supply. Is this trend continuing? Does Tesla expect this trend to continue for the full year? Look for some color on this topic.

An update on China: In an interview last month in Detroit, Tesla CEO Elon Musk said that its rollout in China didn't go as well as expected. While he went on to say that the weaker-than-expected demand was temporary, more optimism about the market on Wednesday would be reassuring. Musk has previously said he believes China could be just as big of a market for Tesla as the U.S. Does Tesla still feel the same way about the market?

If you plan on tuning in to Tesla's fourth-quarter results, the company's quarterly letter to shareholders will be available at its investor relations site a hour after market close. Listen to the company's live earnings call, which includes a question-and-answer session with analysts, at 7:30 p.m. ET.

Of course, check back at The Motley Fool for post-earnings Foolish coverage of Tesla's quarter.

Editor's note: A previous version of this article gave the high end of analysts' EPS estimates, rather than the consensus as indicated. The Fool regrets the error.  Article has been updated to reflect Tesla's adjustment of the time of its earnings release and conference call.

Daniel Sparks owns shares of Tesla Motors. The Motley Fool recommends and owns shares of Tesla Motors. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.