Use arrow keys to move around the scene.

When using the hand tool, Left-Drag moves when no modifier keys are held down.

Combos with Alt + some other modifier key also work without pressing Alt when using the hand tool.

Press and hold Right mouse key.

Now you can move the view around using mouse and use WASD keys to move left/right forward/backward and QE to move up and down.

Holding down Shift key will make you move faster.

Hold down Ctrl/Command key when moving objects in the scene view, and they will get moved in fixed steps instead of continuously.

Hold down V to enable vertex snapping. This will allow you to precisely place objects together.

Press V, hover mouse over an object in the scene, you'll be able to select a specific vertex on that object. Click vertex and drag it to to some other object and you'll be able to snap selected vertex to a vertex on another object.

Shift+V acts as a toggle of this functionality.

You can snap vertex to vertex, vertex to surface and pivot to vertex.

While having some object selected, move the mouse cursor over a scene view and press F to quickly reveal it in the scene view.

출처: 유니티코리아위키 (CC BY-NC-SA 2.0)