Blender has a few features that are slightly different from most other programs, but you will soon learn to use and love them.
The first one that most people struggle with the most, is "Selecting objects with the right mouse button".
You can change this if you want under File → User preferences → Input → Select with → Left/Right
I would recommend you to leave it on the default setting though. This way you don't have to change it each time you use it on somebody elses computer.
Another feature that you might have to get used to is that blender reacts differently to shortcuts depending on where your mouse-cursor is positioned at the moment of execution of the Shortcut. If you execute a shortcut with your mouse in the "Buttons-Window", it will react different than with your mouse in the "3D-View-Window". It also makes a difference if you are in "Object-Mode" or "Edit-Mode". Whenever a shortcut is not doing what you expect, double-check if your mouse is in the right window and mode!
Blender is extremely fast if you use shortcuts. They work a bit different than in other programs, because in addition to shortcuts where you press a bunch of keys at the same time (for example File → Save: Ctrl+ S) you can use shortcuts sequencially (e.g. "Scale in local z-direction by 2": S ZZ 2 Enter).
You will need a mouse for working properly with blender!
Get a standard three-button-mouse! Apple Magic-Mouse not recommended. "Space-mouse" works!
Many shortcuts make a little pop-up window appear at your mouse-position. Don't move your mouse too much, if not the pop-up will dissapear. (e.g. CMD+N asks for confirmation to reload startup file).
If you don't have a Numpad on your computer, you should activate File → User preferences → Input → Emulate Numpad
Here are some of the most frequently used shortcuts:
After entering in one of the transformations (G/R/S) you can use the X, Y, and Z keys to limit the transform in one of the global directions.
Hitting X, Y, or Z twice will transform in local coordinates.
You can also enter numerical values during the transformation. Don't forget to hit ENTER once you are finished.
(e.g. Scale by 2.5 in local Z-Direction: S, Z, Z, 2, ., 5, ENTER)