You can improve your driving skills by walking. This works best in a reasonably large city, with a meaningful walking distance, and when you walk faster than typical crowd pace. Say, walking 10-15 minutes through New York City streets.
Not only is walking good for you, it is free. And because you can practice below items every day you will be getting good in short order.
Just like when driving, you can walk in smooth arcs rather than rectangles. Are you crossing intersections diagonally or on one side and then on the other side?
Manhattan is mostly built with perpendicular streets. Traversing it at an angle presents the challenge of planning when to cross streets and avenues. The goal, of course, is to eliminate time wasted waiting for a green light at intersections.
When walking in busy times of day at faster than crowd pace you need to get around people. This is a great exercise for looking 2-3 people ahead. If you plan your path 30 feet ahead you are doing well.
As you are looking for the holes, consider contingencies. What if people move over? Can you get around them on the same side further or will you run into a wall and have to switch to the opposite side?
A lot is going on around you. Strive to notice it without turning your head. This is the essence of peripheral vision. With practice you will be able to see more and more at once.
The next step is making corrections to your speed and path still without turning your head.
Looking At Nothing
I find walking to be the best practice of "look at nothing, see everything" mantra. I often walk with my eyes forward but not focused on anything in particular, intaking everything that goes on in front and to the sides, only paying attention to anything unusual.
Walking is a great practice for judging when someone gets to a point that you are also going for, i.e., if you can get around people before a fence/tree/opposing foot traffic.