The board looks fine at fist glance, the only things that i would do are to change the crystal oscillato to a ceramic one thereby removing the need for any capacito on it. Also add a header for in circuit seial programing. Add a seial or usb output so you can coneect it to a computer while its woking, and maybe swap out the l293 for an l298 (they allow a more poweful motor so you have an opportunity to upgrade)