Eye contact is crucial to appear engaging, but too much eye contact is creepy. The Daily Muse recommends using the triangle technique to lock your target without being awkward, especially in job interviews.
Before you try this out, you might want to ask a few colleagues and friends whether you make enough eye contact in conversations to usually appear engaging or not. If you are already doing the right things, there's no reason to change to this "triangle technique". Otherwise:
Draw an imaginary inverted triangle on the other person's face around their eyes and mouth. During the conversation, change your gaze every five to 10 seconds from one point on the triangle to another. This will make you look interested and engrossed in the conversation.
Alternatively, look at their eyes long enough to register their colour. Apparently this feels natural enough to not be awkward, plus it has the added advantage of helping remember names.
The Secrets to Making Non-Awkward Eye Contact [The Daily Muse]