I run a job board that has embraced social media for both the job posting employers as well as the job seekers. It's been my experience that the social media campaigns that focus towards your area of interest are best. Aligning within social networks where you can mentor or be taught offer benefits for both sides and have brought the greatest success. Social media is about sharing. There's nothing wrong with self promotion but the give and take of skills and knowledge where all can benefit is key.
The secret ingredient to getting any job is relationships. Social media is a great way to get a name...and hopefully a work place. THE BEST way to get a job is to do some research on the individual....look at LinkedIn etc...find out where they have been, what they like to do, etc... Find something they have in common they have with you and call them. If you are pleasant and have a reason to call, most people are glad to try and help. If they have nothing for you, be gracious and ALWAYS ask (politely) for a referral to a friend of theirs who might be a hiring manager or other companies they know of in their industry...or nearby...who are hiring. As long as you are polite and respectful of their time, you should be received well. Always ask if they have 5 minutes to talk. If they sound hurried or impatient, kindly ask if there is a better time for you to call. You may not be good at this the first 3 or 4 times you do it, but after the 30th or 40th call, you should be an expert. You just have to ask yourself, "how badly do I want to work?"
Determine the ideal job you want. Define a target list of companies to work for. Find the people who work for or have worked for those companies, make personal contact. Meet in person as soon as possible. Find the hiring managers or better yet the person two levels above where you want to work that would control the perfect job and then create a business case to sell yourself into that job. This medium is just another path the the process and steps remain the same. Only four ways to get work or another sale: 1) network with those you know, 2) direct contact to those you want to know you 3) answering a position posting or request for quote and in this bucket goes all things retail which is nothing more than posting what you have to sell and waiting for buyers who need exactly what you have or 4) work through a broker or recruiter who will get paid to help you.