A Great Description

Headline
Your headline is the space for you to showcase what you do. However, most people on LinkedIn just leave their headline as their current job title. Your headline should help you:
• claim your niche - Social Media Expert driving successful campaigns on a shoestring budget. 800%+ ROI in the past 12 months
• demonstrate your expert status - Tax Accountant CPA | Specialist in family-owned businesses with revenues of $1-$5 million
• provide a direct message to a potential customer - Need capital? Banker for early-stage technology growth companies. Clients include XYZ and ABC

Job Title
You need to optimise your job title so that people can find you: the field gives you 100 characters - use them all!
To optimise the job title so you appear in relevant searches, add related keywords. Any keywords that you may have identified for your headline benefit you in your Job Title field as well. Don't get too creative with your job title. Yes, you might be a rockstar, but maybe someone is looking for a ninja to do the work.

Summary
Use first-person narrative and tell the story behind the face and the skills. Storytelling is a big buzzword in brand strategy: people want to know the story behind the idea, product or service. They want to put a face to the brand.
Your profile is not a resume or CV: write as if you are having a conversation with a recruiter for a job you really want. Inject personality by including your values and passions, discuss what you do outside of work. You want people to want to know you. There might be other people with work experience like yours, but they don't have your personality.