When you go for an inteview, don't wear jeans or excessive jewelry. Women, don't wear a plunging neckline and pants so tight they look like snake skin. Don't wear flip flops. Keep your arms covered, meaning short sleeves, no tank or sleevless tops. Keep your skirts a decent length at the knee.
Men, wear Khakis or dress slacks, no sneakers, no sagging or overly baggy pants. No t-shirts, but polos or dress shirts.
Look your interviewer in the eye and stay upbeat. Don't expect to start at the top. Focus on your skills learned over time, not solely on a list of previous jobs, but WHAT YOU LEARNED ON THE JOB.