They are all monotheistic religions that subscribe to a holy book and ask people to talk to themselves in worship of an imaginary God. Also these religions all have dietary rituals that must be followed at certain times of the year or even foods that you can never eat b/c they are either unclean or will displease God.
Where these religions differ is really a mute point when you consider that God is not even real. All religion is manmade and so is God. That's all anyone needs to know.
I'm not gonna troll saying how they're all primitive, messed up etc. . if you want a serious answer:
They all:
believe in a Messiah, whether they believe he already arrived or are waiting on it.
are Monothiestic
involved Moses, Jesus, Abraham etc.
Believe in a heaven (Judaism does NOT believe in a hell.)
Have religious scriptures (Quran, Bible, written Torah)
They all fast.
"Followers of the god of Abraham". Anything further is dependent on the individual rather than the entire faith path. There are huge differences in practice in each path so I feel it is unwise to paint even each path with one broad brush.
Islam: Kill all that aren't Islamic
Christianity: Convert all that aren't Christian; if not, kill them
Judaism: We had a war, we won, let's eat - or - We had a war, we won, let's fast