There is no magic diet that will increase the chances of sperm meeting egg; the best thing you can do is eat a diet high in nutrients and fiber and cut down on your consumption of highly processed foods. It's also important for couples trying to conceive to get plenty of folic acid, which helps prevent birth defects and can improve sperm count.
And while you may have heard that caffeine can hamper conception, don't toss out your favorite mug just yet. Though there have been reports that women who drank more than one cup of coffee daily were half as likely to conceive per cycle as those who drank less, researchers acknowledge that delayed conception could have been attributed to other factors, and subsequent studies have failed to find a significant link between moderate amounts of caffeine and fertility.
Some research has shown that zinc may improve sperm count, but don't go overboard on any one nutrient. Like so many things in life, fertility thrives on balance.