1. Unsubscribe. The easiest way to avoid email clutter is to make sure you don't inadvertently ask for mailings. Whenever you order online or register for a new account, there is often an "opt in" check box to receive future mailings. It's very easy to miss this check box and forget to "uncheck" it, which will result in many emails from each company, cluttering your inbox. If you do miss this step and receive the emails, unsubscribe as soon as you receive the first email. There is always an "unsubscribe" option down in the fine print at the bottom of the email. Of course, you then need to delete the message to keep the number of messages in your inbox down. You'll be surprised how much this cuts down your email count.
2. Organize your email with folders. I know during the holidays, I exchange plenty of emails discussing gift ideas, coordinating who bought what, or sending links to websites. All of this adds to the inbox clutter. Just as with paper, folders help keep things straight. Start online folders in your email for online ordering, gift ideas, etc. Put all confirmations and order status messages in the "online ordering" folder. It makes it far easier to find the details for shipping dates, missing orders, and returns.
3. Control the catalog pile. Catalog clutter can be tamed if you put unwanted catalogs in the recycling bin right away...like, on the way back from the mailbox. If you must keep catalogs, flip through the pages and find gift ideas, then cut out the pages of interest and put them in "ideas" folder. Even better, as with email, you can "unsubscribe" from catalogs at: https://www.catalogchoice.org/ .
4. Keep it together. As packages arrive (or gifts are bought in stores), put all receipts and paperwork in one folder or envelope. Write a little note about who the gift was for, right on the back of the receipt. Very basic, yet very helpful.
5. Get rid of it. Once the holiday is past, returns and exchanges are made, and the bills are paid, there's no need to keep all of those emails, catalogs, or files of receipts. Start next year's holiday season by purging last year's records. Keep the receipts for things under warranty or big-ticket items, like appliances, but toss the rest. You don't need to keep the receipt for socks and pajamas for years. Really.