Also, I think what Whitevillage might mean is that,
There are two schools in observational drawing: one is drawing the thing how you know it is and the other would be drawing it how you see it. First puts emphasis on form, needs you to understand the object and it's mass and if need be draw the same thing from a different angle without seeing it from that angle (try imagining walking around a sculpture, now do that in your head). The other doesn't want you to question what you're drawing too much; ignore that you know that it is a bottle, just draw it, just draw it as you see it even if at first you think what you see is weird and if you're consistent enough it'll come together. Both are valuable skills and with experience you'll know when/where to use one and where the other. Both can be applied to drawing from imagination as well. You're kinda trying to take the easiest parts from both: knowing what you're drawing (but not understanding it, not imagining it like a sculpture) and trying to draw it as you see it (but constraining yourself with what you know of it). god, I'm a horrible explainer.
I think so far you are drawing things how you guess they should look like from a very certain viewpoint but if you are guessing things then oftentimes one makes mistakes and if you guess too many, in this case, bodyparts you make different mistakes and distortions in different ways/directions in each of them and in the end the thing as a whole doesn't make sense anymore, it doesn't come together (these mistakes can happen even if you use reference). That is why you should always think three dimensionally, like you could walk around it and it would look put together from every angle.