Male Veilds have a spir on the hind feet and the base of there tail is bigger due to the storage of there " manly " parts lol (hemipenis) , this can be seen in hatchilings makein veilds the easiest chams to sex, females do not have thses spirs.
Male
Female
these were the best images i had to sow this.
Other chameleons are harder to sex when very young but the base of tail, coloring, shape of casks all are signs of the sex Some chameleons are extremly hard to sex and some are easy.