Few things are more annoying or time-consuming than working your way through spam and an ocean of other emails from companies whose marketing material you've somehow opted into. Luckily, junk mail filters keep the majority of this sort of mail out of your inbox. Unfortunately, though, it's inevitable that some messages you do want to read will make it into your junk or spam folder by mistake.
Check your spam or junk folder at least once a week to make sure nothing's slipping through by mistake. Most email programs, whether client or Web-based, have a function that allows you to mark any mail you do want to receive as "Not junk" and move it to your inbox. Any mail you receive from the sender in the future then goes straight to your inbox.
Reduce the sensitivity of your spam filter. Not all email applications offer this feature, but some programs allow the user to change the sensitivity of junk mail settings. If you find that a lot of your important mail is frequently finding its way into your spam folder, you should consider reducing your program's junk sensitivity. Consult your email application's help section or online support pages to see if it has this function.
Add important email addresses to a "Safe list" or "Priority inbox." If you receive some email that you simply must read as soon as it's sent, and you can't risk it being diverted to your junk mail folder, add the address of the sender to your program's safe list. This ensures that any mail sent from the address you enter always appears in your inbox. Again, some programs do not offer this feature. Consult your email application's help section or online support pages to see if it has this function and how to use it if it does.