Don’t preach loud because Islam is peaceful
Don’t preach Islam to Muslims because Muslims already
know Islam
Preach humanity and consciousness to the mankind which is
lacking today

Don’t preach differences of Islam with other faiths which divide mankind

Preach uniformity of Islam with other faiths 

More than preaching about belief, worship, commands, faral, sunnah, sharia, supplications, repentance, istigfar and rewards 

Preach about attributes of humanity

About love, peace, unity, harmony, sincerity, modesty, tranquility, generosity, sensitive to injustice, selfless, simplicity

Help the man to awaken himself and find his own being and serve humanity

Without serving humanity man can neither believe nor worship God in the fullest sense

Preach uniformity within the diversity which unites mankind
where man can find the seed of wisdom