Once there is an object in your scene of any kind, you will likely want to transform it to better suit what you’re aiming to create before you go into polygon editing.
By clicking the ‘Select and Move’ tool (Shortcut: W) you can use the gizmo to move an object around a scene. By dragging the Red arrow, you move things along the X axis, Green arrow does the Y, while blue does the Z. (See my 3d theory post for more details on that). Dragging an arrow will let you move the object along the corresponding axis, but by clicking and dragging the small square between two arrows, you can move the object along two axis at the same time. You can also click the centre and free move it, but it won’t end well.
Right of the ‘Select and Move’ button is Rotate (Shortcut: E) which will let you rotate an object along the X, Y, or Z axis. Similarly to Select and move, you can click between two axis to rotate along two simultaneously. Don’t recommend. While rotating, you can click on the angle snap button : to snap the rotation to increments of 5 degrees. Very helpful if you want precision – good luck rotating something 90 degrees exactly without it.
Finally, there’s Scale (Shortcut: R). Scaling will allow you to stretch something along a specific axis. Dragging one of the gizmos lines will scale the object along that axis, and exactly like the others, you can scale it along more than one at the same time. DO NOT SCALE ALONG ONE AXIS AFTER UV UNWRAPPING. Dragging the centre of the gizmo will let you scale the entire object, which can be really useful.
All of this can be done by dragging, or can be edited manually by changing the values at the bottom of the screen for maximum precision.
Other useful things.
If you have more than one object in a scene, or have one low poly and one high poly object, you can ‘Align’. This will let you align the two objects with each other exactly.
Mirroring will let you create a duplicate of an object along an axis. Good if you’re doing a fence for example, as you won’t have to model every single post. Mirroring is more accurate, but you can also hold ‘Shift’ and drag to create a duplicate of an object, or multiple if you have more than one selected.
Changing the pivot point of an object.
Changing the pivot point of an object allows the point from which an object is transformed to be changed. Most objects will default to having their pivot points at the base, while spheres will always have their pivot point at the centre.
To do this, select an object and click the ‘Hierarchy’ tab of the command panel –> Adjust Pivot –> Affect pivot only. This will apply all transformations to the pivot instead of the object.