Whenever I speak with HR professionals, receiving a resume that is full of irrelevant skills and experience is their top resume pet peeve. Don't force the HR department to sift through irrelevant information to get to the most important information. Chances are good that they will move on to the next, more relevant candidate if you include irrelevant information.
Your resume should demonstrate that you have experience performing the functions of the job for which you are applying. If you are making a career transition, it is imperative that you do your research and define your transferable skills.
Your resume must include your employment history, complete with dates of employment. A resume without dates waves a giant red flag for an employer. Automatically, employers begin to question why you chose to leave off the dates. Doubts creep in about how old your experience may be and they can't tell how many years of experience you bring to the table.
It is much more effective to prove you possess a skill through a proven track record of accomplishments. Instead of making empty assertions about your abilities, demonstrate your ability to utilize those skills through previous accomplishments. Whenever possible, make those accomplishments measurable with dollars, percentages, hours, numbers of people supervised, and other figures that quantify what you are capable of handling.
Whenever possible, hiring managers are looking for industry-specific experience. If you are making an industry and/or career change and you don't have industry experience, this presents a challenge. Be sure that you do your research on the industry, the job, and the company before sending your resume. Determine the keywords that are specific to the industry and be sure to work them into your resume through your transferable skills.