Your inbox should be a temporary landing space and not storage.
(You don’t review your mail and then put it back in your mailbox to save for later -or at least you shouldn’t- so don’t do that with your email).
Professor Robert Talbert said the following about getting to inbox zero, "Inbox Zero is the state of having your email inbox empty, or nearly empty, at all times. It also refers to the mindset of approaching email with rigorous, disciplined management rather than just letting stuff accumulate" (excerpt from here).
Labels
If an email isn’t immediately actionable (or actionable today), a label should be set up.
Snooze
Use this if you want to have an email resurface in your inbox at a later date. This can be used in conjunction with creating a task or calendar event. *Do not use this to put off emails for a day or you will be in an endless cycle and it will become counterproductive.
Filters
These can be used if you always want certain emails to automatically be filtered in some way.
Templates (also referred to as canned responses)
If you use the same reply or send the same email over and over, a template can be created to save time.
Here are some tools you may find helpful to use in conjunction with your email-
Grammarly- Chrome extension that will grammar check your emails
Unroll.me- Cleans up your inbox by combining subscriptions in one email and allows you to unsubscribe easily.