Ask peers or connections for feedback when you update your profile...
Don't ever be tempted to write your profile in the third person. It makes you sound pompous and distant.
Say "I am David Petherick", not "David Petherick is..." and talk to the individual who is reading your page, someone who is just your kind of customer.
Imagine you are speaking to a friend - write as if you are talking to that friend, one to one.
Once you've written a draft of your profile, try asking someone who does not really know your "business persona" to assess it - perhaps a family member - or ask a connection on LinkedIn by emailing it to them.
The objective feedback they give will help you to improve your profile, and you will also pick up on areas where you have not explained things clearly. They also may spot some typos or grammar errors!
Other people, if asked to give an honest assessment, will quickly spot gaps and pick up on unclear, cliched or redundant phrases. They will spot when you are faking it or talking in ManagementSpeak Gobbledygook BS.
Just follow me, David Petherick or connect on LinkedIn and ping me a message there or via Twitter @petherick.
My email is david@doc.scot - I'll give you a free 10-minute assessment of your profile's strengths and weaknesses and send them to you.