Ambition. It's the engine that drives progress.

If you're an ambitious person, congratulations! Your desire is admirable, and just what employers want. Chances are, you are always seeking to trade up. Better clothes. A better car. Better health. Better productivity. Better performance.

And, of course, a better job. One with a higher salary, better benefits, more responsibility, more opportunities to create change.

Which means that you may sometimes find yourself considering applying for jobs for which you are not fully qualified -- at least, according to the job description. Instead of 10 years' experience, you may have six. Perhaps you lack the required diploma. Or maybe you're inexperienced with a given software package.

Should you still apply?

Sometimes, the answer is no. If the job requires a certification that you don't have, your best bet would be to get certified before applying. And if the hiring manager is looking for 10 years' experience and you only have two, then you should not expect to get an interview.

But sometimes the answer is yes. It's the old "chicken or the egg" question: Which came first? How will you get the experience ... without a chance to get the experience?

It could be that the "required" degree is not essential to the job. And it's possible that in your six years of experience, you've accomplished as much as others do in ten. If something like that is the case, start thinking strategically about how to market your assets, rather than your deficits, and make a play for that dream job.

Applying for the job:

Write a killer cover letter. You're not going to stand out from the crowd based on your stellar qualifications, so get yourself noticed by telling a story that shows how well suited you are for this particular job. No boilerplate here: This letter should be very specifically tailored to this job.

Create a targeted resume. Include your objective: a job just like this one. Don't make any claims to skills or experience you don't have. Instead, play up the aspects of your experience that are relevant to the position.

Focus on your assets. If you lack a skill that is required in the job description, identify a related skill that you possess and emphasize that. Don't know Lightroom but you're a Photoshop whiz? Share that skill, and support it with an anecdote illustrating that you're a fast learner. If a college degree is required and you don't have one, think about what the degree represents, such as critical thinking skill, and find a way to demonstrate that skill.

Get an internal referral. You can't control whether or not you have a contact on the inside -- but you can make sure that if you do, you utilize that critical edge! Employers like to hire candidates who are a known quantity, so a solid internal referral will put your name on the to-be-interviewed list, even if your qualifications are a little thin.

Preparing for the interview:

Become an expert. Read up on the industry you are seeking to join in a focused fashion. Set up Google Alerts on industry keywords, so you get up-to-the-minute notifications of new articles in your field. Follow key influencers in your field on social media, and check out the articles they share. Make sure you have a firm grasp on current terminology, and be prepared to use it.

Show them what you can do. Think ahead about what you can do for the company, and shift the conversation in that direction. Got an idea for how they might save money or increase market share? Prepare a short presentation, using slides if you are comfortable doing so. Show that you are innovative and enterprising -- and that hiring you will contribute to the company's competitiveness.

Finally, consider preparing yourself through contingent work. A good staffing agency can place you in temporary assignments that will allow you to test the waters in your chosen field, develop expertise and industry knowledge, even acquire needed skills. Soon you'll be on your way to achieving your ambition, and nabbing that next dream job.