First off, regardless of what people say, Macs are not perfect. As such, they’re bound to have at least one problem looming over them/ you at any given 10th of a second. Most of these we won’t ever know about, or if we do we’ll just ignore them. When a problem arises that you should be aware of and try and fix most of the time you won’t know the basic steps to troubleshoot ahead of calling AppleCare nor have the proper information to have a quick and concise call with AppleCare. Here are some good tips and tricks that I have that you should use when your Mac(s) have issues that you want to possibly call AppleCare about.
Depending on the issue, your Mac will write a log entry to its log database with useful information. To access this log database simply open Console.app in /Applications/Utilities. You’ll want to click on the All Messages query in the sidebar (the topmost choice). Then look in the resulting list for potential log entries that could have been written when you saw the issue happen. If you know the time (to the minute-second) of the issue just look for entries written then, otherwise just use common sense. If the issue relates to Airport, then any entries that mentions Airport are ones that may be related to the issue.
Then copy all these entries out to a plain text file for safekeeping. Also add any notes of your own related to the issue into this file. If the issue happens on another day it is good to have one file per day for this kind of careful (and quite useful) logging.
Also note that AppleCare will not consider a problem a problem unless it persists across both a PRAM (NVRAM for Intel) and a PMU (SMC for Intel) reset. To perform a PRAM/ NVRAM reset hold down apple-option-p-r while booting up your mac and wait until your hear the Bong 3 times. To perform a PMU reset for PowerBooks and iBooks, for flat panel iMacs, for Power Macs, and for PPC Mac Mini follow those links. To perform a SMC reset for Intel laptops, for Intel iMac and Mac Mini, and for Mac Pro follow those links.
It would also be good habit to restart your Mac at least once a week to remove any anomalies that may be with it and to clear out the system caches. Enjoy, Alex.