Try the first technique to help you manifest your positive intentions for change.  It’s effective used as an adjunct to meditation.  And #2& 3 are great to quickly ease stress-if you have an office or privacy they can even be done at work.
1.  Sankalpa– that means a short phrase, like an affirmation repeated when the mind is most open.  So when is that?  When can we access the subconscious mind most effectively.  When we are in shavasana (yoga deep relaxation.) I will assume you are familiar with it from your classes and can do this on your own.)  Or you can add it at the end of class when you are led by the teacher.

• Simply repeat 3x mentally, a short phrase of what you would like to manifest in your  life, a quality or result.  Examples for more peacefulness:  I am peaceful even in difficult situations. Or, Peace is my response.  I exude peace.

Qualities such as patience or joyfulness, gratefulness can be cultivated this way.
2.  Tension Release Practice-This is often part of the lovely relaxation at the end of yoga class.  You an do it in a chair at work if  you have privacy.  H: hold deep breath in for 3-5 seconds, then exhale through the mouth slowly.  Making a soft “ahhh” sound helps. Release the muscle tension

• Sit in a straight back chair
• Flex the feet lifting toes up,  at same time press knees out to side while using hands to press in (like an isometric exercise) So arms and legs tense.  +H.
• Press low back into chair, contract abs.  At same time raise shoulders up. + H.
• Arms-make fist with hands lock elbows + H.  Then after release stretch fingers wide apart and release any residual tension from making fist.
• Finally scrunch face make a prune face + H.  Raise and lower eye brows quickly and open the mouth wide as if to yawn to counter any residual tension.

End with eyes closed or lowered, and 2-3 min of simply being aware of whole body from feet to head and then from head to feet.   Breath slowly and calmly open eyes and go on with your day.
3.  Breathing Practice– Here is a simple form of deep yogic breathing that can be done for 5 min.

• First sitting up straight, a chair for back support is nice.  Take a few deep breaths.
• Then place one hand on your belly, below the ribs.  Begin to notice the rising of the abdomen as you inhale, and the deflation as you breath out 5-10x.  Can you gently increase that movement.
• Then using both hands cup your side ribs feel the breath now not only in the abdomen but in the expansion of the ribs too.  Keep shoulders relaxed.  5-10x.
• And finally place your fingertips 1 inch down from your collarbones in the upper chest.  Now feel the rise of the belly, the expansion of the ribs and finally a slight lift at the top of the chest 5-10 breaths.
• End by resting your hands down in your lap.  Take a minute to notice how you feel before going on with  your day.

Kalavati Viv Williams is a holistic wellness educator, writer and artist.  She combines her 17 year practice as a certified yoga teacher, massage therapist and longtime mindfulness meditator into her offerings.  Her blog:
http://www.embark-lovethelifeyoulive.com/