Wait at least four days from the most recent use of your fireplace. This will give the embers time to cool and minimize the chances of a spark.
Use a wet/dry vacuum or a fireplace shovel to remove the soot and ash from the fireplace. If using a shovel, dump the ash into a trash bag. When using a shovel, cover the ashes with used tea leaves or coffee grounds to minimize the dust that can fly when you scoop them up.
Place the bag, either from the vacuum, or the one that you shoveled the ash into, into a metal trash can, after tying it off to prevent spillage. Place the can where it cannot tip over and spill the contents. It is safest to keep the ashes away from your house in the event of an accident. However, you live in an area with high wind, you may be better off to leave it inside.
Dispose of the bags on garbage day by placing them on the curb with the rest of your trash.