What is the Christian belief for the route to heaven? There are almost as many of them as there are Christian denominations, and that's alot.
At the simplest level, it's some combination of (Muslim) faith and "good works" (to other Muslims).
Of course, if you actually read the Koran and learn Islamic theology, killing a few Jews, Christians, and infidels helps a great deal.
I wish I remembered the sura and number of that verse that says that the day will come when the Jew (descendent of apes and pigs) will hide behind a tree, and the tree will speak "O Muslim, servant of Allah, there is a Jew hiding behind me, come and kill him." (or very similar words to that effect)
This is the stuff "holy" books are made of.