Keeping the Schedule
While it is somewhat important that you pay attention to the schedule, it really is not your responsibility to make the schedule. It's the AD's responsibility to create a schedule that is right for the project. If that means you have to go over an hour to light the scene to the directors specifications, it should be done unless production steps in and says they can't afford it. At that point it's up to them to talk to the director and negotiate an alternative solution. It is important that the AD is aware though of time it will take for any specific setups that are requested. It can't be assumed they will know how long it will take you to light a scene. Furthermore if they say it must be done in a short amount of time, then it is up to you to request more labor and equipment to have it done. If the current plan is not possible to do in the time alotted, it's in your best interest to let them know that you will try your best, but do not think it is feasible given the time constraints. Be diplomatic, but make sure it is clear.
With that being said, there are a few helpful tricks to keeping the schedule close at hand.
Using Call Sheet
This is called "keeping score". You'll fold your call sheet down so that you only see the scenes or the shots that must be completed for the day and as you complete them you check them off.
Using Phone
You can also do this on your phone by taking a screen shot of the schedule zoomed in, then using markup make solid colored boxes around the top and bottom of the screen. Set this as your phone lock screen so you can quickly reference this throughout the day. This will give you room for your time and any icons below so they don't get buried in the text of your schedule.