As I wrote before, respond quickly to email. I’d say 4-5 hours would be the max when you are trying to impress someone. I would always respond that day. But if you are reaching out to someone who is not expecting it, the rules are a little different. Generally speaking, you should email between Monday afternoon to Thursday afternoon. Don’t email in the evening or on weekends. Why? Because if you do, your email could get buried. I had one student email a potential contact Friday night, and he never heard back. Turns out the email was buried under hundreds of others by Monday morning. Two more quick tips, which I’ll get back to later. First, a strong subject line is key. If you were referred by someone, that should be your subject line. Whatever your strongest connection is to the person should be in that line. Second, be brief. No one wants to see a long email from someone they don’t know.