The Best Job Search...

... occurs when you are already happily employed.

The best job search happens when you are happily working already, are not desperate, and don't have to switch jobs.

The best job candidates are those who are happy in their current position and are therefore relaxed when they interview for jobs.

The worst job candidates are those who are desperate to get a new job and show their desperation during interviews. Hiring managers can smell desperation. No one wants to hire someone desperate.

You can't always predict the future (ie. you might not predict being downsized) but it doesn't hurt to at least keep your eyes open for new opportunities even if you are happily employed.

Also, don't let yourself get complacent in your current job.

"Looking for a job" doesn't necessarily mean sending out resumes and interviewing either.

You might just keep your eyes open for a good opportunity and stay aware of what jobs are available in your industry.