Sometimes, it depends. In a professional setting I might do more eye contact than when I'm hanging out with a friend smoking a j and talking while we lean over a railing somewhere.

as @context@hexbear.net said showing active listening is IMO more important than where you look at someone while you talk, but again the importance of eye contact is contextual.

if you want to practice eye contact, try looking in only one of their eyes vs some random space on the face (ie: between the eyes, or the nose or mouth)