Put a cm or two of wine/water, onions, carrots etc in the roasting tin under the meat to collect and flavour all the juices and make sure they don't catch. I would make (or buy some posh) chicken stock too to let it down and bulk it out a bit.
When the meat is done, seive the pan juices. Spoon the fat (plus some butter if there isn't much fat) back into the tin on the heat, and sprinkle in some flour. Scrape it around the pan to cook it out and get all the gooey bits. Add the rest of the pan juices, some wine and stock and boil up until the texture is right. You can also add port/cranberry/red current jelly/Madeira or whatever else you fancy!