If I have a new job. First day,I will greeting a co-worker with a friendly and say "hello" also smile that is the first step in a workplace relationships.
Learn who works best through email, phone, instant messaging, or personal visits and try to utilize these preferences when engaging your coworkers. Some people prefer email since they like to keep a written record of their actions or responses to questions (or they may be online late at night getting caught up). Others will value a phone call more since it's a quicker medium of communication.