First off, don't self-select yourself out just because they say "top whatever %." If you're interested in a firm, apply. They'll do the selecting for you. And you will be more likely to get something with LR on your resume.
That being said, your chances of landing something via OCI are slim to none being top 50% - hell, it can be extremely difficult for something in the top 20% to land something from OCI. Fact of the matter is, a very, very small percentage of all law students get jobs handed to them on a silver platter from OCI.
To improve your chances, start networking immediate (as in start yesterday). Join local bar associations (there's most likely one for you county, and there may be a city one as well if you're in a large metro area); most offer student membership. Attend bar association events, general ones and ones in areas of law you're interested in. One great thing to do (and I never have, but have heard of people having a lot of success this way) is to attend CLE (continuing legal education) in areas you're interested - you're sure to meet a TON of practitioners in the field, make some great contacts, and impress people with the fact that you're self-motivated and willing to learn. Apply to every job you can, but you may want to focus on smaller and mid-sized firms. You'll be much more likely to get a job through your own devices than hoping OCI hands you one.