First off, there’s no special trick to taking balanced-fill flash pictures outdoors in daylight, even in bright sunlight. With the camera in any automatic exposure mode such as Program (P), Tv, or Av, just pop-up the built-in flash by pressing the flash-on button, or alternatively mount and turn on an EX series Canon Speedlite flash unit. The camera “knows” the flash has been activated, and all you need to do is focus and shoot the picture. In the Tv and Av modes, if you’ve set a shutter speed (in Tv) or aperture (in Av) that simply won’t enable a proper exposure of the daylight in the scene, the opposite value blinks on and off in your viewfinder; just switch to a different shutter speed or aperture, until the display stops blinking on and off. You’re ready to take the picture.
There’s no need to take the flash out of its automatic “E-TTL” setting (unless for some reason you want to use manual flash with an accessory EOS speedlite). The beauty of fill-in flash with a modern SLR is that the camera adjusts background exposure and flash exposure automatically, with little input required from the user.