as with most beginners you're making the classic mistake of only seeing the surface form.
Try looking through the object to percieve what going on underneath.
There are key points to look out for on any kind of bipedal form. Working from the top down, these are;
- Dome of the skull
- Jaw line
- Nape of neck, Clavicles and points of the shoulders
- Elbows
- wrists
- knuckles
- finger joints to tips.
- Thoracic cavity, including Sternum (Middle line from Nape of neck to Diaphragm) , Pectoral orbs (Chest) and Diaphragm (Lowest part of ribs)
- Round of the belly / solar plexus, obliques, lats
- Pelvic Girdle, points of the hips
- Knee joint
- Ankle joints (inner and outer ankle are slightly off set)
- Heel to Toes.
Try to visualise all these on the model your using in terms of balls, ellipses, and lines connecting them, that way you start to SEE within the object and it makes it easier to build on it.
Knowing and understanding muscle groups from human anatomy can be translated to other mammals so long as you understand how evolution has modified certain elements to adapt to each creatures circumstance. For the most part all mammals have the same underlying structure, albeit altered in terms of bone and muscle length and size.
Once you have that basic (what I call) armature, you can then complete the surface form knowing what's underneath.
This gives you a good 'roadmap' to work from.