I'm sure there are as many ways of modelling as there are modellers. So this is just how I would go about creating your piggy (PS. I havent figured out how to make proper armor yet).
For the body and limbs I would start with making a dummy with as few patches as possible and tweak it into size and proportions. No need to stitch the arms and legs on the torso and time consuming things like that, just to get the shape right.
Then start modelling the various pieces of armor on top of these (arm guards, greaves etc) and possibly take a trip to your local museum to see some medieval armor and note how they are strapped on, how the joints are made and such. I find it easiest to start from the shoulders and work my way down. One thing I think is important with armor is to also give the pieces depth, so it doesn't look flat from the wrong angles.
For all of this you only need to make one side of armor. You can later copy and flip for the other side.
On the head I would start with the mouth and snout, modelling these seperately. Then add the eyes to the snout and stitch it together. Then expand with the cheeks and the rest of the face. I would also make the ears as seperate pieces of geometry and stitch them on when they look satisfying.
Always think of what size your final result will be in (you can hide alot of sloppiness on a 64x64 piggy). If the model is only to be shown in small size, then I think texturing is more important than accurasy in the model.
Looking forward to seeing the piggy cut some bacon.
Peter