I don't really know to be honest. I find images and/or quotes that I like and I just experiment and play around until I find something that I like. and occasionally I'll find a style that I really like, so I find images that are appropriate for that style, and then I'll get bored, and find a new style. in reality, it probably looks really thought out and all that but tbh I just muck around until I find something that I think looks nice.