The WTBTS uses a multi-pronged approach when it comes to supporting their unique doctrines.
Because they have a hierachical social structure the rank and file of the membership cannot interpret Scripture for themselves. They must accept the interpretations and doctrines that the "Governing Body" dictates because they are the only "channel of communication" that God uses today. Anyone who “pushes ahead” of the organization and disagrees with the authorized teaching is removed from the congregation and isolated without explanation to prevent others even from knowing why these persons were removed. All contact with such persons is prohibited. Moreover, in a conversation you will almost always encounter at least 2 JWs together. In such encounters they will almost never concede to any arguments against their position because otherwise the other JW will most likely report them to an elder and this could potentially lead to being reproved or questioned and then possibly disfellowshipped.
They re-interpret words and passages and since 1950 they also use their Bible translation (New World Translation) to support their own unique doctrines. Their translation specifically tries to erase or dilute the scriptural evidence for Christ's deity, the Trinity, the existence of the soul after death, eternal punishment, etc.
Their leaders are adept at exploiting the fact that some words in a language can mean more than one thing, which can lead to various interpretations. In these situations they choose meanings that support their preferred religious views, or at the very least undermine traditional interpretations. They use a "this means that" method of linking unrelated verses together to provide scriptural support for their doctrines.
The task of the apologist is to provide the reasons why their methodology and interpretation for each doctrine is not correct, and what the correct interpretation should be. This involves understanding their arguments and understanding the Bible and how to use the principles of interpretation (hermeneutics) correctly.
They use "Special Pleading" a lot. A simple definition of special pleading is: "If X then Y, except when it hurts me." They will use principles and logic when it works in their favour, but silently ignore them when it works against them. I'm sure most of them don't even realize when their own arguments work against them in other areas. For example, they will argue against the Trinity because that word doesn't occur in the Bible, but not realize that they also use many words that don't occur in the Bible.
The famous "Comma Johanneum" of 1 John 5:7-8 has to be removed from the Bible because it doesn't exist in the oldest manuscripts (this is correct and a good principle) but we get to add words to the Bible (in Colossians 1:15-20) that have never existed in any manuscript to support our doctrine that Jesus is a created being.
The word “parousia” has two definitions in Greek dictionaries: coming and presence. In the NWT they only translate it as “presence” to support their view that the signs of Mat 24 are indicators that Christ is present and not that they indicate that Christ will soon be coming.
When the word “proskuneo” (worship) is used for Christ, they translate it as “obesience”; when it refers to the Father it gets translated as “worship.”
They exploit the fact that some words can have both a literal and a figurative meaning and use that fact to interpret passages as being figurative rather than literal when it works in their favour. They use passages in which an invisible “presence” can be legitimately understood to then assert that passages that refer to Christ's second coming are therefore also to be understood as invisible.
The word “eye” can be used in both literal and figurative senses, so they assert that passages that refer to Christ being seen at his second coming they say this actually means figurative sight, not that people will literally see him.
The word “firstborn” can be used literally and figuratively. So when it gets applied to Christ they claim it has a literal meaning to support their doctrine that he was created, rather than that he received the highest honour or position resevered for the firstborn.
The word "only begotten" (Greek: monogenes) can have a literal and a figurative meaning. When it refers to Christ they interpret that as a literal meaning to support their doctrine that Christ is a created being.
When an anarthrous noun (a noun without the definite article “the”) is used of Christ in John 1:1 they exploit that to translate that “the Word was a god”, even though most other times when God is used without an article they translate it as “God.”
They claim that they have faithfully translated the oldest manuscripts and thus they omit several passages (containing 240 Greek words in total) that are not attested in the oldest manuscripts. However, they use the word “Jehovah” 237 times in the NT when it has never been seen in any NT Greek manuscript.
The WTBTS has used the word Jehovah in the NT 237 times as a smoke screen. They claim that the tetragrammaton (YHWH) was still used in speech by the Jews at the time of Christ and that he and the early Christians still used it in speech and in writing. They claim that it was in the original NT manuscripts but that they were replaced by later copyists. They claim that every time the word "name" is used of the Father (as in "hallowed be thy Name") that it originally meant “Jehovah.” It is undoubtably true that the Father is referred to using the term "kurios" and "theos". It is also undeniable that these same terms refer to Jesus Christ in some contexts. They have translated the term "theos" as “Jehovah” specifically in places that refer to Jesus or where OT quotes which use the tetragrammaton get applied to Christ. By relabelling those passages as referring to the Father, they weaken the evidence that Jesus is God. They then have also used the word “Jehovah” in many other places where it gets used of the Father in order to avoid the accusation that they only used it where it applies to Jesus. They are hoping that you will not recognize the pattern and the real motive, which is denying the Deity of Christ and removing any support for the Trinity.