A model of the glucose molecule
A reproduction of a DNA strand
An overview over geometrical shapes and their classification
An abstract model of the circulatory system
Make yourself familiar with the controls for rotation and the flexible geometrical objects before you start building a model. These will both be very helpful.
Models often use the same building block several times. For this, the alt-shortcut comes in very handy: Press the Alt key, click on an object on the stage and drag it. This will make a copy of the object.
Sometimes a basic shape for your model might already be a combination of several objects. Group them permanently so that you you can move, elevate and copy all at the same time.
While building you should keep changing the camera perspective to make sure that you actually put the object where you thought you put it. Perspective can easily play a trick on you.
With models, it does not always make sense to look at them in VR – but it can be a nice bonus, once you’re finished.