the most common cause of tough baked poultry is overcooking in dry heat - use a new thermometer (one that doesn't require poultry to be 190-200 F internal) - and follow the guidelines on the bird package.
I`ve had good results with every bird I`ve cooked that had the little pop-up thermometer in it, and it takes out the guesswork. I don`t know what temp they are supposed to pop out at, but I don`t recall a dryness problem happening. I do a lot of basting of the bird - perhaps that helps.
