As common as this may sound, most of the invitations that people receive on LinkedIn tend to be generic. However, if you want to become a LinkedIn expert, you should understand that people you invite are highly likely to accept your invitations if you can explain slightly why you want to connect with them. As a matter of fact, serious professionals will consider generic invites lazy and amateurish.
To avoid this, every time you send a generic invite, strive to send a message or InMail to the person you were planning to connect with and explain to them why you wanted to connect to them. People make mistakes but taking your time to explain yourself to your future connections can go a long way in strengthening your relationships. It also makes you stand out from the crowd and appear professional.