I used to get anywhere from 10-12 emails a day from daily deals, restaurants, and other places. It was nice to have emails in my inbox...but it got a little hard to keep on top of if I wasn't constantly checking and taking care of them. Nothing drives me crazier than having unread emails in my inbox. I can't see which ones are important!
So, I've started to unsubscribe, unlike, and un-follow! It is so nice to only see a few emails in my inbox at a time, and I don't find myself going to websites and being tempted by restaurant deals to places I don't really like to go anyways, or trying to print of coupons that don't ever work. I know that some people have better luck with coupons printing, and also find the daily deal websites useful: but I'm sure that there are a few emails, blogs, etc, that you could unsubscribe to. Or facebook pages that you can 'unlike', now that you got the coupon you wanted.
Usually, the unsubscribe button is at the bottom of the email. It will sometimes take you to a page to confirm you want to unsubscribe. Sometimes this doesn't work though: in that case, I mark the email as spam, or create a filter so it won't come into my inbox again.
Also, sometimes there are emails you don't want to unsubscribe to. For example, I really like getting the free birthday emails, etc. So, using the handy features in Gmail, I sent up a filter to send these emails to a different folder, so they bypass my inbox. Then, I periodically go into the folder and delete the emails, check for coupons, etc. When my birthday rolls around, I will go and find the email offers that I want to use for my free meals. My favorites are the Famous Dave's coupon, Culver's custard, and Red Robin's free burger (though that one comes on a card, not an email, now).
One last tip...when you open an email, reply or delete/archive right away! No need to open multiple times before you act. That really helps cut down clutter.
As silly as it is to have a 'clutter free' inbox (it's not like it's a physical location in your house), it really does give you some peace of mind. Just like it would if you decluttered a messy room in your home.