If we distinguish our products based on gender or age wise, what key factor should focus on displaying windows or any form of visual merchandising?

First we have to consider our marketplace. For example, your location is surrounded  by schools. Perhaps, brights and interactive displays would help when highlighting products in windows. Inside the store, segregating products by gender or age would be great for easy shopping. Likewise, provide an appropriate signage for each area. Proper product zoning will also help.