My personal tips based on nine months of job searching/applying immediately after graduating college:
1. Re-write resume to each job you apply for. This can be daunting and time consuming, but if you're applying for a job that has specific requirements in the job description, you best make sure those same exact descriptions are in your resume for your past experience.
2. Don't focus on what your hard copy resume looks like, this will rarely get handed out, instead focus on a plain text resume that can easily be submitted electronically. If you're emailing it to a human, a nice PDF with limited styling will work.
3. Key words, make sure your job experience has the SAME keywords as the description for the job you're applying to has. You may think your past job was "X" "Y" "Z" for your duties, projects, etc, but the job you're applying for may say "A" "B" "C", make sure yours says the same. Key words are what these third-party job application programs search for when they scan resumes, you want yours to come up in the results.
4. Limited styling. Bullets, underlines, bolding, font size, etc should all be clean and limited. I limit myself to a one page resume. Eventually after I gain 10 years of experience, I can move on to a two page, but in my opinion, if you're under 10 years, limited yourself to one page.
5. Objective. Throw it out, not needed.
6. Skills. List the skills you have and list the SAME exact ones in the description of the job you're applying for. Example: I know Photoshop, InDesign, Illustrator, and they're all part of the Adobe Creative Suite. I can't just get by by saying "Adobe Creative Suite". Instead, I write it like this: Adobe Creative Suite 6 (whichever the latest version is), Photoshop, Illustrator, InDesign. If the job is saying it wants photoshop skill, better say photoshop and not just Adobe Creative Suite, the job app program won't know what Adobe Creative Suite is.
7. Create different versions of your resume and save them with different file names like, JohnSmithResume, JohnSmithResume v2, JohnSmithResume v3., etc. I do this personally so I know what my original one is and then the v2, v3 etc are modified versions based on jobs I've applied for.
8. Never lie on your resume. This is absolutely true, however, it doesn't hurt you to say you know HTML even if you don't know HTML. For all you know, they may want someone that has the ability to learn HTML rather than a seasoned pro in HTML. It just depends, but tread carefully on saying you did something at a past job or that you were "CEO" of some company when you weren't.
9. Personal website. It doesn't hurt to have a personal blog/site that lists your experience and has a downloadable link to your resume. Also depending on the industry you're going into, it helps you to have an opinion on the industry. Perhaps posting articles, posting projects, etc. Anything that you can do to showcase your experience further beyond the resume. blogger.com is a great start, it's free and easy.
10. Instead of listing duties on your resume, try to showcase projects you completed and what the results of them were. For example, I created an advertising campaign for my college that resulted in increased traffic to the website where students were directed to from the ad. That was one of the goals of the campaign, to increase traffic, and it worked.
I think that's enough for now, if you have any other questions, feel free to ask me.
EDIT:
On cover letters, unless they request it, don't waste your time writing them. If you're emailing your resume to someone, it doesn't hurt to write a few sentences introducing yourself and saying why you would like to have an opportunity to speak further about the position and the company.
The greatest strategy for job searching and applying is to not waste time. You can waste so much time and it will stress you out like no other. As an experiment, next time you are applying online for a job, try timing yourself and do it for several applications and compare how much time you spend applying for just one job.
Sometimes a single job app can take over 45 minutes, especially if you factor in re-writing your resume, and filling out all the forms, etc.