Player Motivation!

I picked up a book on gameplay and design from the library and found a section on player motivation which I thought you might find useful to know as well. Here is a summary:

Each task in your game must have a victory condition with a reward of some kind. This will motivate the player to complete the task.
The values of the task must be seen to be worth striving for.
Always make the player feel like he can actually do the task.
Include various types of motivational devices to lure the player into your game.
Always inform the player of his next goal and tell the player the value of the reward (i.e what they will receive) for reaching the goal.
Make the goals progressive and the rewards equally progressive.

Regards,
Sam