To achieve a better approval rate:
- Never use the default "I'd like to add you to my professional network on linkedin".
- Give some context and info, even very preliminary, as to why you’re asking to connect.
- Try to personalize the invite message as much as possible. Growth-X allows you to include the person's first name in the message. This has proven to increase acceptance rate. But beside a person's name you should try to include information that you already know about the receivers. For example - if you searched for people with the title "Graphic Designer", located in New York - than try to use "Graphic Designer" and "New York" in your message.