Many moons back I had written about using multiple emails forwarding from one to the another etc to handle spam - well that is now done very well by Gmail. So out went Thunderbird [Mozilla email client] - it is still a fantastic product so long as only you use your desktop PC.
So you use Gmail and have been doing so for a while or have just started - never mind - there is always a starting point.
You should also be using Firefox or Google Chrome web browser - it has sooo many addons for Firefox. Chrome - as it is also known as Chromium - the source from which Chrome is compiled - also has addons.
I came across this fantastic addon - ActiveInbox - it uses labels to help you manage your email.
What is missing???
Google calender integration into gmail allowing me to put dates or flow control on my email - apparently the ActiveInbox Plus - the advanced version has it - but at a cost ;-).