When you suddenly develop anxiety, panic, anger or find some mental stress which Mindfulness practice is most appropriate? and why?
Mindfulness of consciousness. Everyone is different. Some will focus mindfulness on sensations or body, but for me, I focus first on consciousness, I ask myself, what consciousness do I possess right now. Here, you cannot accomplish it without Dhāraṇā.
Satipatthana is the establishment or arousing of mindfulness, as part of the Buddhist practices leading to detachment and liberation.
Traditionally, mindfulness is thought to be applied to four domains, "constantly watching sensory experience in order to prevent the arising of cravings which would power future experience into rebirths," namely mindfulness of the body (kaya), feelings/sensations (vedanā), mind/consciousness (citta), and dhammās.