reference reference reference

Hunt the net for reference photos. Take your sock off and draw/model it. Get a digital camera and photograph it. Download the reference photos from www.3d.sk (costs to join). Buy some plasticine and model it.
In maya, try modelling it, bin it and try again. Re-read the tutorials after each attempt and try and apply what they talk about. Try simple shapes and when happy move to advanced detail.

I'm not trying to be nasty or anything, just to give you ideas.
Those links were quite nice for general viewing of the foot shape though.
Just found a couple more for you:

https://www.animationartist.com/2001/...eet_part1.html

https://www.3dtotal.com/ffa/tutorials...farc/body1.asp

As with the second link, its a general body modelling tutorial so maybe searching for those might give better results.
Good luck