For long-term investors and short-term traders alike, earnings season demands everyone's attention. As the best opportunity to get a report card on a company's progress and to test investment theories against what a company actually accomplishes, quarterly earnings reports have a wealth of information that can move not just individual stocks but entire markets.

This time around, things are different on the earnings front. After three years of generally positive expectations for companies to report overall earnings growth, analysts now expect a quarter of declining earnings for the market as a whole. That overall nervousness could amplify movements in both directions when individual companies report surprising results.

If you're not prepared for earnings season, though, it's easy to get blindsided. So even though earnings season officially started last night, it's not too late to consider ways that you can get yourself ready for the inevitable volatility and surprises that you'll face in the coming days and weeks as thousands of companies tell the world what they've accomplished over the past three months.

1. Pay attention to the information that's important.
Everyone gets the same information from the quarterly reports their companies make, but different types of shareholders interpret that information differently. For short-term traders, headline earnings-per-share numbers often determine the initial reaction to an earnings announcement, and so trying to guess what that initial call will be is clearly the paramount consideration for the trader trying to get in and out of a position quickly.

For long-term investors, though, looking beyond the headline numbers to try to find information and detect trends that could have a big impact on earnings not just now but well into the future takes on greater importance. For instance, with Apple (AAPL 0.38%), it's short-sighted to pay too much attention to figures for a quarter that included only a tiny portion of the iPhone 5 release and no sales at all of a potential iPad Mini or other devices as yet undreamed of. In fact, long-term investors may hope for an overreaction to a temporarily negative number if they believe that future quarters will more than make up for a short-term blip.

2. Watch for industry trends.
Given the thousands of companies that will report earnings in the next month or so, it's easy to get tunnel vision and focus only on the stocks in your portfolio. If you do that, though, you'll inevitably miss some information that will prove essential to the prospects of your stocks.

As an example, take the oil services industry. In reporting second-quarter earnings, Schlumberger (SLB 0.44%) went first, topping analyst expectations on a strong quarter with promising trends around the world despite overall macroeconomic uncertainty. Baker Hughes (BHI) reported the same day and had similarly impressive results.

Investors in Halliburton (HAL 0.76%), which reported three days later, could have taken comfort in that report -- and sure enough, Halliburton posted a similar earnings beat. Yet even though Halliburton shares rose on its report, they started rising on the day Schlumberger posted its financials.

To be sure, companies in the same industry won't always move in lockstep like that. But by setting expectations, the first company to report can move the bar for those who follow it, and the information that peer companies provide can move your stock.

3. Avoid knee-jerk reactions.
You should go into an earnings report knowing what you're expecting to see but also having an idea of what types of surprises you might run into. You can't predict every possible piece of bad news, but if you think about at least some of them, you'll know in advance how to handle it. That in turn will keep you from reacting emotionally.

A great example is Best Buy (BBY -1.80%), which opened down 10% and fell even further after announcing terrible results, ending share buybacks, and suspending guidance. By the end of the trading session, though, the stock had recovered to just a 1% loss, and since then, it has stayed relatively stable. Even if you eventually decided to sell the stock, you would've done a lot better by avoiding a knee-jerk reaction and waiting for a better exit point.

Get ready
Like it or not, earnings season has begun. By taking these tips to heart, you can survive whatever your companies' quarterly reports throw at you.

Tune in every Monday and Wednesday for Dan's columns on retirement, investing, and personal finance. You can follow him on Twitter @DanCaplinger.