Chopping fresh or canned tomatoes with a knife on a cutting board works well, but can leave a mess afterwards with tomato juice and seeds to clean up. Real Simple magazine's web site suggests using kitchen shears to cut tomatoes directly into a measuring cup or other vessel to avoid the mess.
We've previously covered how to mince herbs using a similar method. When your marinara sauce is simmering, mince your basil and add it at the end just before serving for the strongest basil flavour.
New Uses for Office Supplies [Real Simple]