How will it kill you?
Most likely, seeing as you're fleshy and human, by poking you with a sharp stick. Failing that, it can shoot blue spheres of pure energy that look like they could be recreated in MS Paint, but will nonetheless f**k your s**t up.
How can you win?
The Predator's weakness is honor. Even Schwarzenegger realized this, since he noticed it butchered everyone in the film except for the helpless woman they had taken hostage. Using this knowledge to your advantage, smear yourself with feces and crawl weeping toward it. Wrap yourself around its shin and rock back and forth, making as much mess and noise as possible. The Predator will ignore you out of sheer contempt.
Also, it seems to have a bomb built inside it somewhere, activated by pushing buttons on its wrist.
If you can wait until it's asleep and turn that thing on, all you have to do is run.