Keep the colours soft and coordinated with your skin tone. A new and current hairstyle will give both men and women a modern contemporary look. If you've been going to the same hairdresser for years, try someone new. Get a referral from a friend. Men, you may love your barber, but you'll be amazed at what a hairstylist can do.
Hair colour is a personal choice.
If you have grey hair and feel it's not a positive attribute, talk to a professional hairdresser. Make sure your nails are well groomed. Women, if you wear polish, keep the colour soft and coordinated with your clothing and makeup. Nowadays, the workplace is more informal. As you research a company or industry, research the dress code, as well.