There's nothing more overwhelming than opening up your email and being greeted by 10 new emails on top of the hundreds that you still have in there. It's easy to lose track of what you need to do. One of the ways to stay on top of things is Inbox Zero and Merlin Mann invented it. It took me over 6 months to attain Inbox Zero, and let me tell you that it wasn't easy. I had a few hundred emails in my inbox and going through them took a while. Well, sorting through most of them didn't require long. There were just a couple of emails that just stayed in there and that I hadn't addressed. After a few weeks of having less than 10 emails in my inbox, I finally managed to clear the all out. Since then, my inbox is always empty after I finish addressing them all in one sitting.
I've implemented Inbox Zero with Gmail since the archive system works really well. Once email is archived, it disappears from your inbox, but can be found again if you need to. You'll need to enable the "Send and Archive' button in Gmail Labs. This automatically archives an email that you've just sent. If you don't, you'll have to manually archive it.I treat my inbox as a to-do list. I go through my list and address it all. Since I rarely get more than 20, it's something that I can do in about an hour, maybe less. This is one of the reasons why I don't check my email more than 3 to 5 times a day. I could easily lose a lot of time if I knew immediately when I received email. So I suggest that you disable all those smart email notifiers, because they'll be just creating your more work.
You'll have to learn to let go. Let go of some emails. Don't delete them, just archive them. Make sure you label them correctly though. I created virtual folders with labels by using the '@' in front of some labels. This means that these labels will always appear first, no matter how many I might have.
You'll also need to let go of constantly checking your email. As someone who has worked in technology for years, I know it's something hard to do, but unless you have some specific reasons why you need to be notified immediately of something, ie you're a doctor, health professional, network administrator, etc, you don't need to check your email all the time. In fact, you can probably create a buffer email for your mobile device, different from the one on your computer, so that you don't get all those work-related emails on your smartphone. However, if you've set up your Gmail inboxes correctly, meaning that your main email serves as a hub email, slaving all of the other emails addresses that you've got, like the buffer email I mentioned before, then you can still address those emails.
Attaining Inbox Zero also means that you procrastinate less. I don't know about you guys, but I have been known to procrastinate. Inbox Zero stops me from doing so. In fact, you'll morph from a someone who procrastinates from time to time to a GTD'er, someone who Gets Things Done.
I also ensure that I don't pollute my incoming mail stream with a bunch of newsletters, Facebook notifications, etc. I keep it clean and simple, making it less of a hassle to deal with stuff when it appears in my inbox.
Some tasks can be addressed immediately, but some need more time. For this, I keep lists. How? I use a simple .txt file that I keep updated with my latest to-do lists. I constantly update this, and modify it as tasks get done. For example, if I have to send a bank wire to someone, I'll copy and paste this info into a .txt file and archive the email. Once it's done, I delete the info from the .txt file.
Sometimes, I even use lists that I've written up on paper. It's very satisfying to cross things out on a list like that. Don't be afraid to scribble stuff all over the place if it helps you address it in a timely fashion.