so the first step you should take on is the design phase come up with some concept art or even just rough sketch so that you know where to head with your next step
I would also like to take this time to mention this is a very difficult process and takes months of hard dedicated work but if you are so incline you to can make something like this.
Step 1: Finding your model
for our design we wanted a short petite woman so we found a model to suit our creature
thanks again to our model
now we must make a body cast so that we have something to sculpt and create on. if you dont know how to make a body cast you can find more in depth methods online and maybe even on instructables but its fairly easy to learn. here are some progress shots of the process.
we did our arms seperately in alginate .