I believe it is important to be fully conversant with your own faith before even thinking of attempting to evangelise others. Especially the more complicated doctrines.
Discussions with Muslims is like fighting with both hands tied behind your back as you cannot Quote the bible as proof as its corrupted ( they say with no real proof ) but of course they can use the same corrupted verses when it proves their point. Of course you can’t suggest there is anything contradictory in the Quran but they will say there is no contradiction as some verses are literal and others need the interpretation of a learned Immam if there is apparent contradiction. Of couse they will see you as a prime target for conversion and the first lines of attack are fairly obvious;
The Quran is perfect ------- don’t accept that but dont get into a discussion about whether it has been corrupted or not. Point out the obvious that corruption of text neither proves or disproves the truth of the text. So a lie repeated pefrectly for a million years and by a million people will still be a lie. Then if you want to stay in this area ask them ; why ,where, when and by who was the Bible changed and any changes they find how has it changed any doctrinal beliefs of Christians. Also how can they know its been changed if they can’t find an original.
The Trinity ------- its not that they can’t get their head around the idea they wont and will continue to try and say we are worshiping 3 gods they will say its pagan in origin and is illogical anyway. Dont waste time here but point out that an athiest with an unbiased opinion will say its just as illogical to believe in 1 god as to believe in 1 god with 3 independant but unified natures so why not just agree to differ as we both know as humans we can never fully know or understand Gods nature. As far as the pagan trinity didn’t the pagans believe in an afterlife so does that mean believing in an afterlife is therefore wrong, whether pagans believed or didn’t in some idea doesn’t make it true or false.
When did Christ say he was God in the bible ---- When did he say he wasn’t and anyway it would have been inconsistant as Christ’s method of teaching who he was ; was through his actions and words, his teaching of the scriptures and meanings and his miracles and what the people had seen then to ask them, Who do you think I am? They have to believe in the Virgin birth as its in the Quran.
Mohhamed is prophiesed in the Bible; which one? the corrupted one?
christianchallenge.org/ask/Mohammed.html not a bad read
then ask who is this is this Mohammed.
Isaiah
For to us a child is born,
to us(Q) a son is given;
(R) and the government shall be(S) upon[d] his shoulder,
and his name shall be called[e]
Wonderful(T) Counselor,(U) Mighty God,
(V) Everlasting(W) Father, Prince of(X) Peace.
What about the one to come after Christ well we know thats the Holy Spirit ; the Paraclete.
The Gospel of Barnabas ---- Medieval Forgery easy to read up on any impartial website
These are some thinks I have found but theres plenty of Answering Islam websites but you need to be carefull not to come across as too antagonistic as they really believe.
The key to converting anyone to Christianity is Christ you must focus the discussion on him and everything he said and done and then ask Who do you think he is?
As far as the Crucifiction being a Fake ; its one verse in the Quran read even the muslim problems interpreting it literally; and why would God go to such lengths to promote a Lie; is God a liar ; has he ever shown himself to be a liar would God ever try to lead people astray. Why if he didn’t want Christ to be crucified would he let him be taken in the first place and suffer so much.
If Christ did die then they have to accept his ressurection as they believe God lifted him bodily to heaven.
I think we should be more intrested in protecting Christians from the attempts of Muslims to convert them by teaching them more of their own faiths and they problems inherant with Islam. Prevention better than cure.
But above all pray pray pray because only Christ can open their hearts to recieve.
I hope this helps