One way to make a project more challenging for older kids is to add more steps. For example, if you are making a collage, you could have them first sketch out their design, then cut out the pieces and glue them down. Or, if you are painting a picture, you could have them first draw it out with pencil before they start painting. By adding steps like this, it will make the project more challenging and take longer to complete, which is ideal for older kids.