Once you have completely updated and filled out your LinkedIn profile, then you can join groups. Groups are an incredible resource and very powerful way to increase the reach of your LinkedIn network. While you can join up to 50 groups, I suggest you initially focus on joining ~35 leaving yourself room to add new groups in the future. If you’re using LinkedIn for job hunting you want to join groups related to your industry, profession, and expertise. If you’re using LinkedIn for prospecting, then join groups where your target prospects would participate. I find groups great for establishing credibility and helping me focus my networking activity. Groups connect you to people relevant in your field, just like attending a networking event does. Join the larger size groups you find, avoid small or inactive groups. Make it a point to occasionally post to each of the groups you have joined when a topic you can contribute on is being discussed. Be aware that LinkedIn will remove you from a group if you don’t contribute.