Learning time management skills is part of growing up. Most kids find it challenging to keep track of time and lean on parental cues to get things done. Teaching our kids to be pro-active rather than reactive is a skill they can use for the rest of their lives.
Timers: One way to keep track of time while you are engaged in an activity is to use a timer. I use timers everyday, both personally and professionally. My main use of timers is to alert me to wrap up my current task so I can honor my next commitment. Timers can be helpful for kids too! Use them to signify transition times like mealtime, bedtime, and when the bus is coming.
Calendars: Post your children's schedules in a place they can reference it. This will help them learn accountability around managing their own schedule. Calendars you might post include: lunch menus, sports schedules, and after school activity schedules.
Chore tracking: Children thrive on positive reinforcement. If you want them to help out around the house, provide incentive. Give them a tool to track how close they are to earning their reward. Our family has tried fancy charts, marble jars, and a simple piece of paper with hash marks signifying a chore well done. Each of these systems worked for a short time when we (the adults) were consistent with using it. We have found the most success when we switch it up by changing the tracking tool periodically (i.e., every 3-6 months).
Just like any other new behavior, give it time and give your child reminders to use these tools.