I found that I am more effective and efficient when I am punctual. If I need to be somewhere at 9am, then I make sure I leave in time to arrive at 8:50am. This means checking weather/road conditions, knowing the directions on how to get to where I'm going and also making sure that those I'm taking with me are ready also.
I have all the clocks in my house synced up to each other and for my kids, I have added alarms to their phones so that they have a count down as to when we are going to leave. I have also set alarms on my phone to remind me to go warm up the car.
By having simply things done the night before, like backpacks and purses are ready, it is easier to leave when it's time with out a last minute scramble.
That's what works for me!