First, let us see meaning of the word 'देव'(Deva). It is derived from the root 'div' (which means 'to shine') using pratya (Ach -ka). So Deva means someone shining.From 'Deva' we get 'Devata' by ('Tal' pratyaya). Deva and Devata means both deity and God as per the Sanskrit Lexicons.
Tri-Deva or Tri-Devata means the three principal deities :Brahma (Creator),Vishnu(Preserver),Shiva/Rudra(Destroyer).
Ishta-Devata is one's Chosen Deity. Normally Ganesha, Surya,Vishnu,Shiva and Shakati---any of these five or their incarnations is the Chosen Deity decided by the mental inclination of the worshipper.For example, to a Shaiva, Shiva is Ishta-Devata or Bhagavan where the other forms mentioned above are Devata, which are His manisfestations. Normally while worshipping Ishta-Devata, all these five forms are to be worshipped.Worshipping them together is called 'Panchopasana' also and these five deities called 'Pancha-Devata's.
Upa-Devatas are also Devatas and can be translated as minor deities. In any puja, we worship 'Indra, Varuna,Agni,Kuvera,Vayu etc as Dasa-Dikpala's. In the Dik-pala list,some major gods are also there. see https://en.m.wikipedia.org/wiki/Guardians_of_the_directions for reference. Khestrapala also has to be worshipped. The Pancha-Devatas are worshipped normally with pancha-upachara(Gandha-Pushpa-Dhupa-Dipa-Naivedya), while the Upa-Devatas are generally worshipped with Gandha-Pushpa alone.
In Tantra, there are methods of worship of Dakinis, Yoginis ,Yakshinis and Apsaraas. They are also minor deities able to grant 'bhoga' or 'bhukti' alone but not 'Mokha' or 'Mukti'.
Apa-Devatas are inferior deities, like Bhuta,Preta, Pishacha,Rakshasa.They are first worshipped by Gandha-pushpa and offering 'Masha-bhakta-vali' and then driven out of the place of worship alongwith Sarisripas by the 'Bhutaapasarana-Mantra' by throwing sveta-sarshapas (whte mustard-seeds).
In Tantra, there are methods of worships of Pretinis and Pishachinis to attain occult powers. These are also inferior deities.
Hope this answers your question. You can check any puja-paddhati book for more details.In Bengal, we adore the books written by Shayamcharan Kaviratna.
Tanrik-Guru by Paramhansa Nigamananda also discusses various sadhanas of Devatas, Upadevatas and Apadevtas.