
Don't do it for the money. Everything else aside, given the loans you'll likely have to take out, you won't see much of all that money during your first years in a new legal career--and if, in addition to that, you also hate what you do, then no amount of money will make your life seem less miserable.
If there's one thing I wish law school hopefuls would do is really think about what they want to do with the degree, rather than just focusing on "getting in." Sure, getting into a good law school is an exciting experience, and having that J.D. will undoubtedly give you a great sense of accomplishment. But what you should really be focusing on is what a J.D. will allow you to do within a career path, and how happy that particular career will make you.
It almost sounds a little "self-helpish," but I always tell students to focus on what will make them happiest, and then tailor their educational and financial plans to fit. If money makes you happy, then I guess that's a good a motivator as any, but chances are there's a lot more going on than just a desire for money; try to keep the money aspect out of it. Otherwise, once the money is gone (or if it never comes along), then all you'll end up with is an expensive degree that makes you unhappy and forces you to do work that you'll find unfulfilling.
Like Eliminator said, just focus on working on getting the best LSAT you can. Then thoroughly think about what you REALLY want to do with your law degree, and set a path in motion to achieve that.