After years’ worth of emails in my account, it becomes harder to find things. Google has some great tools to help you. In your email account, you just have to add them in the search window.
bill. If you enter the beginning of any name, the full contact information will pop up (3 different Bills, in my case, Bill G., Bill P., and Bill S.) Click on the one name to find all the messages from that person.
label:unread If you have lots of unread messages scattered throughout your folder, collect them all together and read them one after another. Bonus: Check all of them, then uncheck the ones you really want to read, then mark the others as read. Like below. Use with any folder name too: label:inbox.
after:2015/03/30 If I want to find an email and know it was in April, this is a great way to limit the search. Works with before:2015/04/30 to limit it to April only. Use both together. You can also use older: and newer: with dates.
has:attachment If you know there was an attachment on the message, a great way to get only messages with attachments.
You can combine these together. Happy hunting!