All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Tawheed ar-Ruboobiyah means believing that Allah is the only Creator, Cherisher, Sustainer and He is Alone who takes care of all the matters of worlds. Whoever believes that Allah has a supporter in these matters or that someone other than Allah carries them out, he commits Kufr.
Tawheed al-Uloohiyah means Allah is Alone and worthy of true worship. Whoever entitles a portion of worship or a form of worship to other than Allah, he commits Shirk. For instance if someone prays to a creature, idol, tree or makes Tawaf of such things to get reward of Allah, or makes sacrifice to them, etc. he performs Shirk in Uloohiyah since he sets partners in the worship with Allah.
Tawheed al-Asma-wa as-Sifat means approving and believing in all the Names and Attributes that Allah has described for Himself such as al-Rahman, al-Raheem, al-Azeem, etc. No one is allowed to give Him a Name other than the Names and Attributes that He gave to Himself or His Prophet Muhammad gave Him.
This is the method of true followers of Sunnah in this matter. When they approve of the Names and Attributes of Allah they do not believe that they are similar or like those of His Creatures.
Allah Says (interpretation of meaning): {….There is nothing like unto Him, and He is the All-Hearer, the All-Seer.} [Quran 42:11].
Allah knows best.