I made a LOT of mistakes on LinkedIn before finally stumbling upon a few techniques that seem to work. My intention in writing this is to help you skip the mistakes and go right to what works:
1.) Pick ONE focus for your LinkedIn profile.
Fuzzy profiles don't work. You may be a famous actor and an accomplished carpenter, but on LinkedIn you have to decide which to highlight. Multiple messages confuse people and ensure you will never, ever get business through LinkedIn. I'm not telling you how to lead your life, only how to structure your profile.
2.) Turn your focus area into a short, powerful tagline.
I'm talking about the words that appear right under your name, where I write: ghostwriter. Unless you are President of the United States or CEO of Apple, don't just put your title here. Come up with a phrase that is the perfect response to a search that should pull up your profile. (Important note: since my profession is so rare, I DO list that one word that says exactly what I do. I've tested many headlines, and this one works beautifully for me.)
For example, if you are looking to become a goalie in the National Hockey League, your tagline might be: winning college hockey goalie.
By the way - most people IGNORE this strategy; they just list their title. (Most of these people are disappointed with LinkedIn.)
3.) Add a powerful Summary
The difference between a LinkedIn summary and your resume is that the summary can say what you want to do, rather than just listing what you have already done. It should be short, clear and focused.
Here's how mine starts:
Everything about my profile is designed to answer the questions of someone who is searching for a ghostwriter. Is being a ghostwriter the only thing that matters to me in the world? No. But the focus of my LinkedIn profile is to connect me with ghostwriting clients.
Structure your summary to attract the kind of people that matter to you: new clients, prospective employers, or even startups in which you wish to invest.
4.) Strip away the clutter
You don't have to list every job you've ever had. You don't have to describe every accomplishment in every position. Edit your content through the eyes of your desired audience, and cut everything that might confuse them or scare them off.
5.) Invest in a great picture
Nothing bothers me more than a profile picture in which the person has an extra arm around their shoulders, as though they cut their spouse or significant other out of the shot. The same goes for dimly-lit images. This is your one chance to make a great first impression - don't waste it.
If you can't figure out a way to take a good picture, delete your LinkedIn profile. Seriously.