Polytheism means either worshiping something other than Allah or associating partners with Allah. For example: requesting help from the deceased or from idols, as well as loving them, fearing them, making a vow in their name, or slaughtering in their name.
The proof is that Allah says in the Quran
{Indeed, Allah does not forgive associating partners with Him, but He forgives what is less than that, for whomever He wills, and whoever sets up partners in worship with Allah has certainly gone far astray.}
Shirk is of two types: Major Shirk and Minor Shirk
Major Shirk: This involves directing any act of worship to other than Allah. An example is prostrating to other than Allah.
{And of His signs are the night and day and the sun and moon. Do not prostrate to the sun or to the moon, but prostate to Allah, who created them, if it is Him that you worship.}
Minor Shirk: This involves those words or deeds which serve as a vehicle to commit major shirk. An example is making one’s prayer a little longer sometimes or reciting the Qur’an a little louder for the sake of showing off. The Prophet ﷺ once observed, “The thing that I fear most for you is the minor shirk.” His Companions asked, “What is the minor shirk, Messenger of Allah?” He replied, “Showing off.” [Musnad Ahmad: 23630]
You must know that none of Allah's creations is equal to Him. He alone is Everlasting and All-Powerful. It is He Who creates, provides, and knows everything, and no one except Him can be characterized with such great attributes. It is He alone Who deserves praise, obedience, and gratitude.