This is a lengthy article, with several good videos and pictures of some shelters in the midpoint of construction.
The shelters for different environments will help you decide which ones to concentrate your practice builds.
I do wish we had areas around here (Reno, NV) which would allow us to build these shelters. You do need to harvest a fairly large amount of limbs and trunks for some of the shelters. This will be a no-no in our local parks and some forest lands.
I direct your attention to the tools you will need for some shelters: a wood saw for up to six inch thick trees, cordage of various types (no specific type is absolutely necessary, it just needs to be long enough and strong enough).
It is a longer article and worth reading (saving) and watching the videos:
http://deerhuntingfield.com/building-survival-shelters/