A friend of mine who works in the US at LinkedIn shared a list of what makes a good LinkedIn profile and pointed towards the article below.  From all the suggestions here are my top 4 recommendations for setting up a decent LinkedIn profile:

Add (the right) photos - Adding a decent photo makes you 11 times more likely to be found apparently.  Importantly this needs to represent the 'professional you', not the 'sweaty sports you' or the 'party you' or you and your mates.  Here is the one our Marketing Head Sam Pagehas (I am including this as he would only approve this post if I included images :)

Write a better headline Explain what you do but also give something else of yourself - your passions, loves or interest.  This is mine:

Claim your URL  This is really simple to do.  You can customise your LInkedIn URL so it has your name rather than random numbers.  

Click the Me icon at the top of your LinkedIn homepage / Click View profile / On your profile page, click Edit public profile & URL on the right rail / Under Edit URL in the right rail, click the Edit icon next to your public profile URL. / Type the last part of your new custom URL in the text box / Click Save.

Revise your summary This section does not need to be long but it does need to say something about you - not boring CV stuff but a proper description of who you are and your experiences.  This is the hook when people are checking you out.  It can be the difference between whether someone gets in touch or not so spend time on it.

Great example below from my colleague Connor Kinnear:

Now go and check your profile!  Love to hear your thoughts and advice.