Avoid sitting on sofa. sit with erect back supported with pillows, sit on chair designed for posture.
Try to pull your shoulders back while standing to avoid slouch posture.
Keep practising chin tucking exercise for maintaining your neck curve.
While standing weight should be put equally on both legs. avoid shifting weight more on 1leg that will help in reducing your lower back issues.
Most important is your FOOTWEARS.. Wear proper footwear for preventing heel pains, to reduce stress on knee & ankle joints, to prevent developing of calcaneal spur..