"Take therefore no thought for the morrow: for the morrow shall take thought for the things of itself. Sufficient unto the day is the evil thereof." Matthew 6:34
Don't misinterpret this verse and think that we are not suppose to think about tomorrow at all. We are told to occupy until He comes-- raise our families, do our work, live life. If I am planning on taking a trip tomorrow, I have to "think" about the trip ahead of time and make sure that I have my clothes washed and ironed and packed for the trip. If a student has a test tomorrow, they have to make sure they have studied and are prepared to pass the test. If a business man has a presentation to make next week, he needs to be working today to make sure he is ready to present it when the time comes.
The word "thought" means- anxious, worry, fretful. We are told not to "worry" about tomorrow. Don't be fretful, or fearful, don't worry when there is no food in the cabinets today about what you are going to eat tomorrow. Don't be anxious about what may come your way tomorrow because of where you are today.
Sandwiched between verse 31- "Therefore take no thought, saying, What shall we eat? or, What shall we drink? or, Wherewithal shall we be clothed?"-- and verse 34 is the key to not being worried or anxious-- "(For after all these things do the Gentiles seek:) for your heavenly Father knoweth that ye have need of all these things. But seek ye first the kingdom of God, and his righteousness; and all these things shall be added unto you."
When you are tempted to be anxious about tomorrow, remember that you have a heavenly Father who is watching over you. Remember that He loves you and will take care of you. Remember that He already sees tomorrow and makes provision for it. Also, don't seek after your needs-- seek Him. Make seeking Him your priority. Put Him first- first in your time, in your work, in your home, in your thoughts, in your heart, in all you do. There is something you have to do about tomorrow: don't worry or be anxious, remember that God sees tomorrow, just keep your heart set on seeking Him, and give Him first place in your life.
Have a great day. Don't worry about tomorrow- remember God and seek Him above everything else.