By adding -s

Singular	Plural		Singular	Plural
ant	ants		lock	locks
banana	bananas		magazine	magazines
bicycle	bicycles		mongoose	mongooses
cow	cows		nose	noses
daughter	daughters		orange	oranges
egg	eggs		picture	pictures
flower	flowers		rose	roses
grape	grapes		spoonful	spoonfuls
human	humans		toy	toys
jug	jugs		vase	vases
king	kings		well	wells