djb

Have you ever toured before?
given the smaller volume available, keep in mind how one t shirt can weigh half the amount and half the volume of another, and synthetics will dry fast compared to cotton. Same with shorts, long pants. Etc

have fun playing around with your choice of stuff

staehpj1

Also the same stuff can take up more of less space depending on how you pack it. I manage to compress stuff with tiny sil-nylon stuff sacks without needing to resort to compression sacks, but it is a skill that comes with a little practice and as djb says some items pack better than others.