There is ample time in a day to achieve great things. However, the reason you may not achieve much is because of either lack of clarity or lack of focus.
If you are clear about your goals and what you want to achieve during the day you have a head start. If you are one of those people who does things more as a reaction to others as opposed to carving out your own destiny then your outcome from the day will be minimal.
Once you have clarity then you will require focus to execute around what you need to do. If you have clarity but you do not focus on what you know you need to do, then it is almost as if you have no clarity.
Clarity and focus are like two wings of the bird that enables you to fly towards success.