Younger and young are slightly different and they change the meaning of your sentence. For example... "I'm working on a scheme to attract younger customers." This to me tells me that you are looking to attract younger clientele than you currently have. Meaning that their youngness is in relation to your current clientele. For example, if your current clientele is 40-60, then you are looking to attract under 40's. If your clientele is 20-40 then you are looking to attract under 20's. Both are younger than your existing clientele but both are not young - depending on your definition of young. "I'm working on a scheme to attract young customers." This has no relation to your current clientele, it just tells me that you are interested in attracting young customers. Their youth is not relative, they are just young. I hope that helps. If you need further clarification please feel free to message me. All the best, Evie