If you need to send a lot of individual emails to prospects or clients, sending them one by one from Gmail can get pretty tedious. Quickmail is an awesome service that piggybacks onto Gmail and automates sending out these emails. You can put all the details and personalizations in a Google Sheet, and it will know what first name and company to mention in the email and so forth. It’s easy to use and keeps track of bounce rates and open rates and other stats, as well as performing automatic followups and drips.