first you want to draw an outline of the legs using one oval for one thigh and another oval for the other and medium sized circles for the knees. if it is a young character you would add only one more circle for each pair of legs. if an older do one whole circle plus half of another one.
yet this only works with female characters I dont know how to guys... SORRY!!! ^-^
hope this helped
Here is a video on how to draw female anime legs... boys legs shouldn't be too much different... just a little more angular.How do I draw apicute of an amigo cartoon animal?
...How to draw a airplane?