You've got your profile built, now you want to start building your contacts.  You aren't sure you who want to invite to connect with on LinkedIn in the first place.

Before we go into the hows, let's consider the whos.  Everyone has a different take on the people they want in their network, whether it's face to face or virtual.  We're naturally drawn to certain people.  My stance on it is that there's just no way to know everyone well, and there's really no need to. Some people like to collect connections like other people collect MP3s.  My only caution there is that this isn't MySpace, it's a professional site.   Although, if you're in Sales or Talent Acquisition, you want lots and lots of connections, I'd imagine.
 
I like to keep my relationships more substantive, professional and otherwise, so I limit my LinkedIn connections to those I know well enough to be able to talk to other people about them with some detail.  If I can't say more than a best guess about your field, I'm not likely to connect directly with you.  This isn't personal, it's just a preference, and it has no bearing on my opinion of you.  I leave the more casual relationship is up to a group-level.

So think about who you want to connect with on LinkedIn.  Most likely the folks you currently work with, and ones you've worked with in the past.  I started building my network with folks I worked with in the past, and a few close colleagues, then eventually started branching out to people I worked with and respected, but didn't know as well. 



LinkedIn very conveniently offers multiple ways to connect:

Pick your top contacts.  The quick and dirty way.  Sometimes you'll see a field for this on the home dashboard (that first page after you log in).  Literally, all you need is their name and email address. This is best used when you're adding a few names at time.

Choose from your colleagues.  When you have an organization listed on your profile, you will start seeing periodic prompts about new users from that organization on the dashboard.  Click on the link and you'll get a listing.  How much easier can they make it for you?  The hitch is, for free accounts, you only see 50 of them.   However, you can probably guess their email address and use the first method, if you're from a large organization.  This works for schools as well.  The terms in the Help & FAQs section is "colleague reconnect" and "classmate reconnect."

Use Outlook.  I used outlook at my old company, and I use it at home. So I love this; I can upload and download my contacts en masse, between Outlook and LinkedIn.  When you upload to LinkedIn, you can select which ones you want to send an invitation to, as few or as many as you want. 

Now, about the invitations themselves.  LinkedIn has a nice, simple script, which you can either customize or completely replace.  Last year I frequently edited it because people thought it was spam (you will not get spammed from LinkedIn, they function on the concept of "mutual acceptance" and spam doesn't meet that requirement, as you didn't opt in to it).  I like to make it more personal, myself.




Once you send the invitation, you get to wait until the recipient accepts it, or rejects it.  You may find you have invitation requests piling up; don't take that personal.  Not everyone responds immediately, although etiquette would be to respond in a week's time if not on vacation.  When you reject an invitation, you can customize the response if you wish.  You can re-send and remove invitations as well.   For more information about contacts and Invitations, go to the LinkedIn Help & FAQ page. It's very useful.

Once you're connected, you can upload the new contact information into Outlook.  You can also see their profile, their recommendations, and their contacts, in varying degrees, depending on how they've set up their profile.  And vise versa; you can customize visibility using Account and Settings.  


Homework
Send at least three invitations to connect, using any of the means listed above.  For the "fast" invites, you can:

On the home tab Dashboard, you can use Quick Invite, if it shows there.

Go to My Contacts and use the Add Connections

Go to Inbox, select Send Message, then Send Invitation

Extra Credit
Check your visibility Settings to customize to your desired level of privacy.