Make a borax solution. Mixing borax powder with water in a bottle and shake the bottle until the borax powder dissolved.
Mix water , glue and shampoo in another bowl.
Add some food coloring or glitter if you want to the glue mixture.
Slowly add borax solution ( 1 ml. per time ) to the glue mixture and stir it until it is thick and have the slime texture that you want.
Add some oil to the slime to make it do not sticking to your hands.
Ready to play!!!