Subhadrika Sen
Try plank, where the posture is like you are doing push-ups, but you hold the posture from 30 seconds to 1 minute which increases strength in abs, lower back and shoulders.
Start with 10 and move on to two to three sets of leg raises. Lie on your back and raise your legs at a 90 degree angle. Hold for 5 seconds and lower them. Perfect for the abs and hips.
For stability and hand and leg coordination try the Dead Bug. Have your knees bent at 90 degree, arms upwards and lie on your back.
For balance and stronger lower back, sit in a table formation and extend one arm forward and the opposite leg backward and do the Bird Dog formation.