Better concentration and focus makes life easier and more productive. But most of us often multi-task and give in to distractions. This leads to procrastinating that then leads to cramming to complete tasks right before the deadline. When people cram, they don’t fully concentrate on the tasks resulting to sloppy work.
For better concentration, stick to your to do list and don't start a new task when you are still doing another.
Lemon oil is great for concentration. Diffuse some while working to keep you going on the task at hand.