The recommended method of using Gmail accounts in Outlook is to use IMAP. However, this only syncs email, not your Gmail calendar and contacts. If you don't have a Google apps account you'll need to use a utility to sync your Gmail calendar and contacts to Outlook. The Google Calendar Sync Utility utility will work with Outlook, however, it only syncs Calendars.
You need to configure the account settings online to allow IMAP (and/or POP3) at Gmail settings. This needs configured only the first time you use Gmail.
Configure the account
If you let Outlook configure your Gmail account, it will set it up as IMAP. If you don't want to use IMAP you'll need to configure the account manually.
Use your full Gmail address, including @gmail.com or @your_domain.com as the username.
In More Settings, Advanced tab, set the Incoming server to use port 993 and SSL encryption. The Outgoing server uses port 587 and TLS encryption.
On the Outgoing Server tab, select My outgoing server (SMTP) requires authentication and Use the same settings as my incoming mail server.
Note: this screenshot is from Outlook 2013; options on the lower half of the dialog in other versions will vary.
Setting a Sent Items folder
Beginning with Outlook 2007, you can choose a Sent folder for your IMAP accounts. While there is no problem using a folder on the IMAP server with most IMAP accounts, you DO NOT want to save a copy of sent items in the Gmail folders. Saving a copy in the Gmail folders will result in two copies of Sent Messages. If you use Gmail's SMTP server, Gmail will put a sent copy in the [Gmail]/Sent Mail folder automatically.
Either configure Outlook to not save sent copies of the Gmail mail or Save it in your local sent folder. Saving a copy locally will result in two copies of the sent message (one local and one saved by gmail online), but this is necessary if you use BCC and later want to check who a message was sent to.
Outlook 2013 removes the ability to choose the Sent folder, instead, it asks the IMAP server which folder it should use. If the server supports XLIST or enhanced-list, or Outlook can match a folder on the server to it's folders by name, sent items will be stored in the Sent folder on the server, otherwise they will be in the local Sent Items folder.
Messages sent through the Gmail account will sync down to Outlook on the next sync, or when you open the Sent folder.
Setting a Deleted Items folder
Outlook 2010 introduced the ability to save Deleted items on the IMAP server. As with sent items, this works fine for most account types but has unintended consequences with Gmail accounts.
The problem is with how Gmail manages email, using Labels instead of folders. Labels are converted to folders for IMAP access. Deleting a message removes all labels from the message, leaving the message in the [Gmail]/All Mail folder, which shows all messages, whether or not they are labeled. To delete a message from all folders, you will need to move it to the [Gmail]/Trash folder.
Moving deleted messages to your [Gmail]/Trash folder will delete the message in all folders. Deleting a message from the Trash folder deletes it permanently.
If you use Shift+Delete to permanently delete messages, they will be deleted in Outlook and from the account online, bypassing the Deleted items folder. They cannot be recovered.
Do not configure Outlook to empty deleted items on exit. It can take "forever" for Outlook to close when used with IMAP accounts. Gmail will keep deleted items for 30 days before deleting them permanently.
Subscribe to folders
You can control what folders are visible in your IMAP clients by subscribing or unsubscribing from IMAP folders.
Right click on any folder in your IMAP account and choose IMAP folders... to open the IMAP folders dialog. Click on the Query button to list all folders or type a few letters in the Query field then click Query to display only folders containing those letters.
Folders displayed with a small envelope icon are subscribed, those without the envelope are visible only using your server's web access.
Select a folder and click the Subscribe or Unsubscribe button to change it.
I do not recommend subscribing to the [Gmail]/All Mail folder. This duplicates all messages in the other folders and will double the size of your data file.
Note that the subscribed folder list is stored on the server and will apply to all devices you access using IMAP. You can't subscribe to all folders on your desktop computer and only the Inbox on your tablet or laptop.
Unsubscribe the All Mail folders
Do not enable Outlook's junk mail filter. Gmail's spam filters are generally better than Outlook's junk mail filter and using both can result in confusion.
Tools in the Spotlight
Do you need a solution to sync Outlook and Gmail Calendar and Contacts when Gmail ends ActiveSync? CompanionLink keeps Microsoft Outlook and your Google account synchronized. Make changes in Outlook and those will update your Google account. And vice versa. Set the auto-sync feature to automate the entire process. CompanionLink works with any Google, Gmail, or Google Apps account.
The WebDAV Collaborator is a powerful plug-in for synchronizing your CalDAV calendar and/or CardDAV contact data to Outlook. Works with Gmail calendar, Yahoo, Zimbra, Zarafa, Atmail, and more. Outlook WebDAV Collaborator is compatible with Office 2013. Outlook 2003-2010 32/64 bit support.
GO Contact Sync Mod synchronizes your Outlook contacts with your Google Mail address book, including pictures, categories and notes. It also syncs your Outlook Notes on demand to Google Documents.
GooOut syncs Outlook calendar and contacts with your Google / GMail account. Stay in the known and up-to-date by synchronizing your Google Account on your Google based smartphones. Sync Outlook Calendar & Contacts with Google Calendar & Contacts, one way sync and Merge possible. No server needed.
gSyncit is an Outlook add-in that allows for two-way synchronization between Google and Outlook calendars, contacts, notes, and tasks with your Google account. In addition, gSyncit also supports synchronization between Outlook and Toodledo, Pocket Informant Online, Evernote, Dropbox, Simplenote and Nozbe. Version 3.6 and higher support Windows 8 and Outlook 2013. Supports Outlook 2010 and 2013 64-bit.
Outlook4Gmail is a free Outlook add-in providing easy contacts synchronization of your Outlook and Gmail accounts and address books.This add-in uses these Outlook and Gmail contact details: Name, Company, Phones, Emails, Addresses, Dates, Persons, Notes, etc. You define the direction of synchronization/update: you can sync or update either the Outlook or the Gmail address book (one-way synchronization) or choose to update both accounts simultaneously (two-way synchronization).
Sync2 is a powerful Microsoft Outlook synchronization software for those who use Outlook on their PC at work, notebook on the go, and on two or three other computers throughout the day. With Sync2 it is possible to sync Outlook folders, such as email, calendar, contacts, tasks, notes and journal between multiple PCs without a server, share Outlook Calendar with Google Calendars, sync Google Contacts and Tasks with Outlook and more.