Vitamins & exercise. Making certain your body has the required nutrients is very critical to managing stress. Also squeeze in all the fitness you can. You don't need a committed hour ritual but 5 minutes here and there will and can make a difference too. Take the stairs instead of the elevator. Park further away and walk vigorously to the office. You may also consider eating a sandwhich or wrap for lunch which is easy to make and consume. Use the balance of your lunch to go for a stroll. Whhile strolling try some deep breathes. This helps to infuse your blood with oxygen and gets it circulating to your entire body. This helps you to think clearer and better.
Here are some scriptures I use to meditate on while I'm at work and while I'm exercising.
Isaiah 54:17 (No weapon that is formed against thee shall prosper; and every tongue that shall rise against thee in judgment thou shalt condemn. This is the heritage of the servants of the LORD, and their righteousness is of me, saith the LORD.)
Jeremiah 29:11 (For I know the thoughts that I think toward you, saith the LORD, thoughts of peace, and not of evil, to give you an expected end.)
2 Timothy 1:17 (For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind.)
Luke 6:27 (But I say unto you which hear, Love your enemies, do good to them which hate you,)
James 2:26 (For as the body without the spirit is dead, so faith without works is dead also.)
1 Peter 2:12 (Having your conversation honest among the Gentiles: that, whereas they speak against you as evildoers, they may by your good works, which they shall behold, glorify God in the day of visitation.)
I hope this helps you tremendously.