There is no question about it: Spam is annoying. However, it is even more annoying when legitimate emails end up in your junk email folder. Here are some simple steps to make sure desired emails get delivered to your Inbox.
In Outlook select "Junk | Junk E-mail Options" listed under the "Home" menu.
Select the desired level of junk email protection:
Unless you have selected "No Automatic Filtering" above, add the desired email address (e.g. email@example.com) or domain (e.g. @casinosoftware.com) to your "Safe Senders" list:
You can also access these options by right-clicking an email that's already in your "Junk Email" folder and selecting the "Junk" option:
Since no spam filter is perfect, it is also good practice to regularly review the emails in your Junk Email folder.
If you are still unable to receive some emails (I generally answer emails within 24 hours), you need to talk to your computer department as they may be filtering certain emails before they even get to you. Just ask them to "white-list" the desired domains or email addresses.
Additional information can be found in Microsoft's Overview of the Junk Email Filter article.