How do I know which one of my actions will meet with Allah’s approval?

Allah always inspires the most proper course of action through the conscience of one who fears Him. In a verse, Allah says: 

You who believe! if you go in fear (taqwa)  of Allah, He will give you a criterion (by which to judge between right and wrong) and will cleanse you of your sins and forgive you. Allah’s favour is indeed immense. (Surat al-Anfal: 29)

It should not be forgotten that the first voice the individual hears in his heart is the voice of his conscience which helps him to judge between right and wrong, and it is this very voice which tells him the behaviour that will please Allah. People who fear Allah arrive at the truth by listening to the voice of their conscience.