You should probably learn by creating a set of challenges for yourself, then trying to solve those challenges. If you bump into problems, you do some research or simply ask other people for help.

For example:

1. Switching to graphics mode then drawing a dot. (I.e. learn how to use graphics.)

2. Have the dot move across the screen in 10 seconds. (I.e. learn how to implement animation.)

3. Draw two dots on the screen, one which is player controlled and one which attempts to chase the player. (I.e. learn interactivity and "A.I." techniques.)

4. Add some walls onto the screen which neither dot can pass through. (I.e. learn collision detection.)

5. Repeat 1-4 with a sprite that looks like a character. (I.e. advance your graphics skills.)

6. Repeate 5 with an animated sprite that looks like a running character. (I.e. advance your animation skills.)

And so forth.