Without knowing your exact circumstances and commitments, I can only offer some broad suggestions on how to improve your time management. As for your motivations, perhaps you are motivated to make better use of your time so that projects are not always being finished at the last minute. It is also possible that you want to better manage your time in order to free up more time for various other pursuits like hobbies or exercise. The following are some standard time management tips.
First, stop procrastinating. This one might sound overly simplistic, but the entire situation hinges on it. If you save everything until the last minute, then things are always going to feel rushed and as if you don't have time to do the task right or well. Starting any and all work as soon as possible is good for time management.
Second, don't multi-task. Far too many people believe that they can effectively do multiple tasks at the same time and do them well. Studies say different. The evidence points out that we can really only effectively focus on one task at a time. This might mean that you don't reply to emails all throughout the day. Set aside a time for email management rather than trying to do emails and grade papers (personal example).
Third, create a to-do list. This sounds archaic, but it works. List out all of the things that need to happen that day. The list doesn't need to be in order of importance. It just needs to include each task that must be completed. As you complete a task, cross it off of your list. This simple act has a way of making you feel good about accomplishing a task; therefore, it becomes a motivating action.