A short guide to landing your first Rails job.
In order of importance:
1. You will be judged foremost by the quality of your code, so have an app you're proud to show off. Aim for small classes, short methods, and full test coverage. More generally, make sure the code is the best work you're capable of. Submitting a code sample and saying "I know this has some problems" is an antipattern.
2. Make friends with at least three other Ruby developers. My first Rails job came to me through the friend of a friend. My second came through an immediate friend. This is how good jobs get filled. You should also ask your Rubyist-friends to critique your sample app.
3. People who are in the market for a programming job should blog every day. Write about what you've learned so far. Don't make the excuse that you're just a beginner. Imagine someone who is two months behind you and write for them. An active blog shows passion, demonstrates skill, and helps you make more Ruby friends.
4. Distinguish yourself from the applicant pool. Particularly because you lack experience, you need to stand out. Doing so is 95% creativity and 5% effort. Your goal is to make your application more interesting than "somewhat promising but inexperienced Rubyist number 32". For inspiration, you can read about how I stood out to get my first conference talk accepted.