You may also want to leave some of the jobs off your resume, if they were very short term (less than six months). Most people live in fear of the gap, but particularly in this economy, it's not unusual for people to have a few months in between jobs, and in your case I think it will look better to have a few gaps than many years of job hopping. Remember, a resume is a marketing tool, not a job application. You aren't required to itemize every minute of your life. You are supposed to use it to sell those skills and qualifications that best recommend you for the job to which you are applying. If you were at a job for only a few months, it's not likely that you acquired any special new skills or qualifications, at least not well enough that an employer will consider them. So there's nothing to be gained by including a short-term job, other than the fear of the gap.
Now, beyond the resume, you may want to consider what types of questions you are asking the employer before you accept a job offer. Try to suss out what their situation is. Ask questions like what is the average tenure of their employee, have they had any layoffs, what is the reason they are hiring for this position, what is their marketplace position/who are their competitors, what their short and long term company goals are, how employee performance is evaluated, etc. Steer clear of jobs where they are hiring just for one account or project, obviously.