Theses look very 3 dimensional for the most part, but I think you are drawing these using a very distorted perspective. I can tell you are using a vanishing point with these, and the problem is that with small objects especially, if the vanishing point is too close to the object you get odd distortions. I would suggest using an intuitive perspective, meaning create a box that looks good and follows the rules of perspective, then use it as the framework for your drawing. I did a couple of very sloppy examples to show you how you can do this, I hope it helps :)