Prophet Muhammad (peace be upon him) said:

“There are no days that are greater before Allah or in which good deeds are more beloved to Him, than these ten days, so recite a great deal of tahleel, takbeer and tahmeed during them.”
(– Ahmad )
While there are different versions, the takbeer can also be recited as follows:
Allahu akbar, Allahu akbar, laa ilaaha ill-Allah, Allahu akbar, wa Lillaah il-hamd.
Allah is Most Great, Allah is Most Great, there is no god but Allah; Allah is Most Great and to Allah be praise.
The companions would go to the marketplace and recite the takbeer aloud, as more people would join in. Let us follow their footsteps and encourage others to recite the takbeer as well, as an act of worship and a proclamation of the greatness of Allah.