Another good way to practice is cut a few sheets of newspaper into a strop sized pieces use a clip from any stationary store to hold a few layers of paper together then hang the clip from a hook like you would your leather strop. Use another clip at the bottom of the strop to hold. (in the UK we call the style of clip a bulldog clip, or at least I do). Practice stropping until your not cutting the paper. When you get confident remove a layer of the newspaper and repeat until your paper strop is just 1 sheet thick. Once you can strop on a single sheet like this then your usually good to go without cutting.