Your brain is not a recycle bin. Filter the information passed to your brain. When you allow too much information at once, your brain opens a door for the subconscious mind. As a result, useless thoughts may control your mind. You will feel fatigue by only thinking of your duties, even if you didn't do any of them yet.
Write down all the ideas that come to your mind to empty your brain's capacity.
Organize your ideas into sections to clarify your aims.
When you organize your ideas you make the process of taking decisions much easier.
Writing helps you to organize your ideas and even brings out new thoughts.
When you write your objectives, your mind will make a flow of information. Hands and brains are connected together, so you may write ideas that weren't clear in your mind before writing them.