I have been in this field for over twenty years and it varies a lot. Certifications help get in the door in some places at least past the HR department. Experience is golden, longevity at the last job is a biggy. Where you live drives the salary. Colleges and schools tend to pay below "standards". I have worked for billion dollar companies and small companies. The big companies provide better benefits but small ones more freedoms.
The big thing is recruiters. There are two types:
Ones that work for you and those that work for the employer.
The ones interested in helping you:
Advantage: Will send you on lots of interviews.
Disadvantage: It is hit and miss on jobs and sometimes send you to jobs you dont qualify for.
The ones that are interested in the employer:
Advantage: If they send you to a job, you have a good chance in getting it.
Disavantage: Getting them to send you a job.
Sometimes contract is the best way to sneak in. I have started some jobs in a low level area but worked up to a nice position.
Salary is the big trick. Once you hire in a place your salary is set in stone. It is hard to change it much more than small raises. I have found that most places if they really want you they will not dismiss you for higher salary. They simply tell you it is too much. They may sqawk but give you something close after that they dont think about it anymore. I have had literally some jobs not hire me because I asked too low. They saw that as a sign of little experience.
One thing about IT is there will always be a need for them. In 2003 there were 1.2 million IT people unemployed including me. It is getting better.