There are many ways to do a resume but there are two TRUTHs that you need to keep in mind when writing and reviewing your resume.
A recruiter will look at a resume for 5 to 10 seconds
We recruiters are a busy lot. Most recruiters handle 20 – 30 openings at a time and we usually have 100s of applicants for each position. You need to get our attention FAST!
Recency and Relevancy Rule
You need to focus on what is recent and what is relevant. I am usually NOT interested in what you did 10 years ago UNLESS it is directly relevant to the position you are applying for.
Why using a summary of qualifications rocks
You get to bring THE most important stuff from your background to the top of your resume. Be sure to bullet it as I do not like reading comprehension tests. You can highlight certifications, training, relevant work experience, etc…
Keep it to 3-7 bullet points. Remember, recruiters tend to be a little ADHD so we want the facts, no fluff. Think of your summary of qualifications as the answer to this question:
Why should I call you about this position instead of all these other people?
Try it out on your resume then A/B test it to see what others think.
Being second is to be the first of the ones who lose.