There is a great blog post over on the Banyan Branch blog on how to use Social Media to help you get your job. Check it out at http://www.banyanbranch.com/social-blog/social-media-for-your-job-search-arsenal
What I want to add to that blog post is a tip on what not to do when applying and that's follow up with the right people and don't get to pushy!
I get so many emails and tweets asking if they got the job, when the right person to ask would be head of HR or possibly a friend or contact that they might have in the company. I personally am so far removed from hiring, I don't even get to see any resumes. So my tip is to make sure you follow up with the right person. Also know what is acceptable when following up. Most likely tweeting at every employee that you know at the company is not a good idea.
Remember to stay positive
Look for opportunities to meet future employers at parties and networking events but also know how to keep the conversation casual. Sometimes I get cornered at a party and leading to an awkward conversation. Instead of asking to be hired on the spot focus on having a great conversation. Leave a good impression.
Last but not least, if you don't get hired at what ever company you apply for, remember to stay positive and don't hold any grudges. There have been a few situations where I have personally witnessed someone lash out via Twitter or Facebook towards a company where they did not get hired. No matter where you live always remember its a small town...even in NYC. People move around, lets say you apply at a start up and the hiring manager denies you. You get angry and 5 years later when your applying at Amazon you could be surprised to find that the same guy who denied you before is the new recruiter at Amazon or worst yet your new boss. So always stay positive and in the end things will work out!