Unfortunately, if you don't pass the initial screening the only thing you can do then is to reapply in 18 months. You of course will need to make sure that during that time you gather more experience, which will make you an interesting candidate for the MBB (internship at a top corporate, startup experience, prestigious degree, outstanding social engagement, etc.).
But the better question to ask is: how to pass the initial resume screen? In your CV focus on highlighting the virtues, which will make you suitable for consulting: leadership, team work, entrepreneurship, analitical skills, creativity. Make sure your CV stands out: are you a marathon runner? Mention it! Do you love 18th century French literature? Mention it!
Also, if you feel unsure about your CV, my advice would be to apply for participation in events rather than for a job right away. Even though the MBBs argue that there is no difference in applying for events vs. actual consulting job, in my experience screening for events is a bit more relaxed and if you prove yourself active and interesting during the event, you will be invited for the interviews automatically. Another important point is that you can apply for events as many times as you want – if you are rejected for one event, you can re-apply for another the next day, no need to wait for 18 months.