Respect is a language with local dialects, but its core vocabulary repeats across cultures. Verbally: use titles and surnames until invited otherwise, greet the eldest or most senior first, let them speak without interruption, and in languages with formal address forms, use them. Asking an elder's advice, or for their blessing in South Asian and some African traditions, is itself a profound gesture of respect. Loud contradiction or joking too freely with seniors lands badly in hierarchical cultures, where disagreement is voiced softly and often privately.
Physically, the signals cluster: stand when an elder or dignitary enters; offer your seat; give and receive anything with both hands in East Asia or the right hand in South Asia, the Middle East, and much of Africa; incline your head slightly in greeting; and avoid towering over a seated senior, looming, or pointing. In some cultures, younger people bow, touch elders' feet, or lower their gaze; visitors are not expected to perform every native gesture, but a respectful head-nod version is always welcome.
With community and religious leaders, add restraint: dress a notch more formally, speak when invited, and accept hospitality graciously. The underlying principle everywhere is attention: the respected person is noticed first, heard fully, and never made to wait on your convenience.