edit the ipv4 connection settings for your ethernet connection to your xbox to be "Shared to other computers" instead of "Automatic DHCP", not sure but you may need a "crossover cable" or "crossover adapter" poof your done, i think some network adapters dont require crossover cables or maybe i mixed up my cables in the past :-)
any router in the middle of xbox and laptop is handy, such as a hub or switch, this will remove the need for a crossover cable. i have an old dsl modem (no longer used as a modem) aka a router, which i turned off "DHCP" and "NAT" options (for most devices make a connection to device with a static IP of something like 192.168.0.9 with subnet mask of 255.255.255.0 and open a web browser to goto web page http://192.168.0.1 to see settings, your device may use different IP's to configure, turn off DHCP on device and its done) now your laptop is a wifi hotspot
if the computers connection to the router is set to "Shared to other computer" then anything connecting to the router will share whatever internet connection the laptop has. This type of connection will put everything behind a layer of NAT and not be a true bridge, your xbox wont care, i know - ive done it
p.s. the daring could splice an ethernet cable and turn it into a crossover, info is on google if you trust random web pages, not recommended