A lot of people are on auto pilot, and caught up in their own world most of the time. Looking at the people around them is the last thing on their mind!
With that being said, some days will be better than others. Personally when I walk around my college there will be some days where no one is making eye contact with me. Other days will be totally different.
Do you have a masculine walk? Do you have a strong, commanding presence? Do you wear bright colourful clothing? What kind of facial expressions are you using when you look at other people? These are all things to consider if you want people to glance at you first, or even look at you at all. It helps to get their attention and makes you stand out amongst the crowd.