The most important step in creating a realistic 3d model of an existing object is to capture the main lines that define that object in space.
After drawing the main lines in two dimensions over the reference images they must now be “bent” on 3d space to form a convincing representation of the model. It helps to have the real object at hand to check how these lines should look from specific angles, diving into more detail where needed.
To have a clearer view of how the 3d model looks like I have been using 360/3D renderings visualized using a VR headset. This allows a clearer perception of where the lines stand in space and their relationship to each other.
Please note that the best way to watch this video is using a VR headset and with full 4K resolution. If you watch it on a desktop all you will see is two images (left and right eye) one on top of the other. You can also watch it directly on an Android device but you will be loosing the 3D part of the experience.