For entry-level positions, the biggest factor these days is building a network of friends, family and professional contacts that can tell you about jobs before they are advertised or that never get advertised. The old truism that the best jobs come through contacts is even more true than ever. And with entry-level jobs pretty scarce right now, it's particularly true for such positions.
Certification counts a lot less than what you know how to do, and what your many years of on the job experience have taught you. Letters of recommendation from former bosses that stress your reliability, general knowledge, attitude toward work, and problem-solving skills will be particularly helpful in your case.
This was first published in September 2002