Thanks for the question.
The best website to search online for a particular job is going to depend on your profession. If you're a M.D. physician you shouldn't be looking on Craiglist for a job. So the best advice here that I can give you is to look for job boards that are dedicated to the SPECIFIC type of job that you're looking for, and in your field, with your credentials.
The second part of all of this is that your resume needs to speak DIRECTLY to the needs of the employer and how your presence will assist them in making more money, or providing some service to them that will take care of an existing problem that they have. So your resume needs to be more than functionally sound. You need to show how you're a "fixer" of sorts by saving x% for the company two quarters in a row or perhaps you streamlined business processes for your former company by saving 24 hours in the supply chain and saved customers money on shipping. Somehow you have to show that you have the power and thought process that brings you to move TOWARD problems to fix them as opposed to just waiting for the next person to address key issues.
Managers and Directors today want to know that you'll save them money, increase revenue in some fashion.
I mention this because you should look to apply to companies where there may not be openings but where you see a problem that you know you can help fix if you were part of the team. If nothing else, the manager that you call to speak with before sending your resume will appreciate the fact that you were wiling to call to help him in some way and you're not even an employee. That kind of outreach stands out in todays employment evironment
I hope this answer helps!! Good luck!