Mudras are easy to perform at anytime, although sitting in the lotus position and focusing on the healing can be an advantage.
Although mudras can be used for healing certain ailments, regular practise of mudras will contribute to your overall good health and can be used as a preventive measure.
Continuous practice of the mudras will create minute changes in your body using pulse centres on parts of your hands, which trigger certain healing processes within the corresponding body part.
Mudras are to be performed with both hands at the same time, unless otherwise specified.
Start with 10 minutes at a time and increase up to 3/4 hour for best results.
Fingers should remain comfortable during the procedure and not held stiffly or tight.
SHUNYA MUDRA & VAYU MUDRA SHOULD ONLY BE PERFORMED UNTIL THE CURING OF THE AILMENT!
Gyan Mudra 
Description: The thumb and index finger are brought together gently while all the other fingers remain upright.
Uses include:
Mental Peace
Concentration
Sharp Memory
Spirituality
Insomnia
Mental Disorders
Stress
Depression
Drowsiness
Develops telepathic ablilities
Developes clairvoyant and extra-sensory ablilities
Apan Vayu (Mrit Sanjivini) Mudra 
Description: Fold the forefinger to touch the mound of the thumb. The little finger should be held erect. Then place tips of middle finger and ring finger together on tip of thumb all touching each other. (BOTH HANDS)
Uses include:
Strengthens heart
Emergency first aid for severe heart attack if administered within 2 seconds.
Self Confidence
Normalises blood pressure
Vomiting
Menstruation related problems
Purifies the entire body
Rudra(Prana) Mudra 
Description: Place tips of index finger and ring finger together on top of the tip of thumb, with other fingers extended comfortably. (BOTH HANDS)
Uses include:
Dizziness
Improves blood circulation
Brings clarity in thought.
Low blood pressure
Improves eyesight
Improves breathing
Controls eating habits
Blocked Veins
Improves concentration
Apan Mudra 
Description: Place tips of thumb, middle finger and ring finger together in each hand. (BOTH HANDS)
Uses include:
Liver
Gall Bladder
Removes wastes products
Toxic release
Bladder problems
Balances mind
Self confidence
Patience
Serenity
Inner Harmony
Prithvi (Surya) Mudra 
Description: Place the tip of the ring finger on top of the tip of the thumb. Extend all the other fingers and keep them comfortably straight as possible.(BOTH HANDS)
Uses include:
Liver
Inner stablity
Self Assurance
Stomach
Strengthens body and mind
Glowing skin
Increases energy
Shankha Mudra 
Description: The left thumb should be held in the right fist and then the left indoex finger should touch the right thumb.Put light pressure with the remaining fingers of the left hand onto the closed fist fo the right hand. Swap over sides.
Uses include:
Thyroid Glands.
Throat
Blood Vessels
Muscular System
Digestion
Good for actors and singers for voice enhancement
Jalodar Naasha Mudra 
Description: Place thumb down on little finger and keep all remaining three fingers comfortably straight
Uses include:
To enhance beauty
Removes impurities from the blood
Restores moisture to skin
Painful cramps
Shunya Mudra 
Description: Place thumb down on middle finger and keep all remaining three fingers comfortably straight.
Uses include:
Relief from Earache
Deafness
Vertigo
Numbness in the body
Vayu Mudra 
Description: Place thumb down on index finger and keep all remaining three fingers comfortably straight.
Uses include:
Relief from Rheumatism
Sciatica
Stiff Neck
Knee Pain
Gout
Joint Pain in hands and feet
Paralysis
Hysteria
Linga Mudra 
Description: Join your palms in front of your chest and lock the facing fingers together keeping your thumbs upright. Hold for 3 minutes, release and repeat twice.
Uses include:
Weight Reduction
Colds and Coughs
Strengthens lungs
Digestion
NOTE : Make sure you drink plenty of water as Linga Mudra generates heat in your body. If your already obesse with excess water in body, then avoid drinking more.
Varuna Mudra 
Description: Join your little finger to the tip of your thumb. Keep other fingers comfortably straight.
Uses include:
Dry skin
Blood problems
Restores moisture to the body
Relaxes muscles ~ cramp
Diarrhea and dehydration
To enhance beauty
Surabhi Mudra 
Description: Join the little finger and ring finger, then join the middle finger and index finger together.
This pose can also be called “cow posture” as the mudra makes cloven hooves of your hands.
Uses include:
Rheumatic inflammation
Sharpens your intellect
Surahi Mudra 
Description: Join the little finger of one hand with the ring finger of the other and vice versa.
Similarly, join the forefinger with the middle finger of the other hand and vice versa.
Leave your thumbs free.
Uses include:
Rheumatic inflammation
Colds
Sharpens your intellect