With sugar (use of sugar in freezing almost always enhances the flavor of strawberries)
Wash & remove hulls, then slice the berries and place in plastic freezer bags--add sugar to suit your taste or the cooking recipe you will be following ( we use about 1/4 to 1/2 cup of sugar to every 2 cups (pint)of sliced berries). Be sure to note the quantity of berries & sugar used on the package to avoid "guesswork" when you use the strawberries later. Tie & put the bags into the freezer immediately.
Without sugar Wash & remove hulls but don't slice, dry on a towel then place on a cookie sheet one layer at a time in the freezer. After they are frozen (usually the next day) scoop up the berries and place in a freezer bag. These berries can then be removed individually for cereal or shortcake during the winter! Try thawing them out half way (don't cook them) in the microwave before you use--- this will take some experimentation with settings & time to get just right. If you take them out of the freezer and allow them to thaw slowly, they will usually be soft, mushy, and not very attractive (but taste OK).