It's that time of the year again. Apple (NASDAQ: AAPL) has just put a date to its first-quarter earnings release. The quarter, which coincides with the fourth calendar quarter, is arguably the tech giant's most important quarter. Not only does it take place during the holidays, but it's a quarter that's marked by the availability of the tech giant's latest iPhone releases.

Apple has scheduled its first-quarter results for fiscal 2018 on Feb. 1. Before the release goes live, here's a preview of what to look for, and what to expect.

Apple customers waiting in line at an Apple Store on the iPhone X launch day. Image source: Apple.

Record revenue

For Apple's first-quarter revenue, investors should have high hopes -- and this isn't just because Apple released the iPhone 8 and 8 Plus just before the quarter began, and the iPhone 10 on Nov. 3. Investors should have big expectations for revenue because Apple management said that's what it would deliver.

Management guided for record first-quarter revenue of $84 billion to $87 billion, up 7% to 11% year over year, or 60% to 65% sequentially. Revenue growth in this range would start Apple off with more momentum than the 3% year-over-year growth Apple reported in the first fiscal quarter of fiscal 2017.

iPhone sales growth

Apple likely won't be able to pull this off without a big quarter from its iPhone segment. The product category accounted for a whopping 62% of Apple's trailing-12-month revenue, highlighting how the product can make or break a quarter. Fortunately, a good quarter from iPhone is almost certain.

iPhone X. Image source: Apple.

First of all, Apple's guidance for overall revenue provided some vision into how iPhone sales were faring at the beginning of the quarter, since the guidance was issued over a month into Apple's fiscal first quarter of 2018. Guidance for strong year-over-year growth in overall revenue suggested iPhone was having a great holiday quarter.

But investors can also expect a big quarter from iPhone because of how robust Apple's lineup of new iPhones was this time around. Not only did Apple launch the iPhone 8 and 8 Plus in late September, but the iPhone X came two months later.

Finally, Apple appears to have benefited from a strong supply of its new iPhones during the holiday season based on how rapidly shipping times slipped during the period.

Strong earnings-per-share growth

Thanks to Apple's aggressive share-repurchase program, the company's earnings-per-share growth should outpace its revenue growth during the period. During fiscal 2017, Apple repurchased about $48 billion worth of its own shares, or about $12 billion per quarter. This pace likely continued at a similar rate in Apple's first fiscal quarter of 2018.