Some key takeaways are:
Be more active on LinkedIn
Update your status daily and comment on updates from the companies you follow.
Participate in (or start) LinkedIn group discussions weekly.
Regularly update your profile information.
Make it personal
Instead of just sending a connection request, send a personal message with the request. This will make you stand out. Write a short message about how you know them, or why you would like to know them.
Use the "Alumni" search feature to find connections from your high school and college. Join LinkedIn groups within your niche and take part in the conversations.
Ask people you know for endorsements
Follow up endorsements from others with a personal thank-you message. Don't accept or provide recommendations from people you do not know, or people whose skills you can't personally vouch for.