This site boasts hundreds of questions about the size of particular creatures and the effect the square-cube law has on them. However these questions usually focus solely on the skeleton and are often answered with examples of Gigantism, which is a growth problem where the body limbs grow disproportionally compared to the organs that try to support it.
As we scale up an insect for example, we know that at some point their method of breathing becomes insufficient and their skeleton will grow too heavy. So we have to use another solution to solve these issues: lungs and endoskeletons. Then as we grow an insectoid creature bigger we know that other problems arise in a set progression, such as the method of leg articulation requiring different methods. The question I'm having is: what does this progression look like when we start scaling from a humanoid size upwards?
As an example for the answer I'm looking for here's a hypothetical answer:
The first thing that needs a solution is the skeleton to support the weight, focussed mainly on the legs and hips. The next thing that gives out are the muscles, which simply cannot create enough surface area on their cross-section to efficiently support its own weight and add more strength to the overall creature. Then bloodpressure becomes a problem... then neurological problems to steer it... then the surface area of lung tissue, intestine length, liver position, kidneys etc.
The goal is to give people with questions a simple guideline to what size does to a creature, and where approximately on the scale of size their creature is going to be and the changes necessary to make it a reality.