The best beginners method is using the "layer method" which I'm pretty sure you're using since you're using the book. Once you get that down, lube your cube using either liquid silicone or Vaseline (however Vaseline can damage the plastic, but not horribly). If you still enjoy solving and want to improve your times more, go for the keyhole method, it will shave about 20 moves off of your F2L, and if you get it well enough it can take off anywhere from 5-15 seconds off of your overall time. Then if you're still bitten by the bug, go for a 2 look OLL, and PLL. With a keyhole F2L and a 2 look OLL and PLL you can get your time to around 30ish seconds, well, I did at least.

Damn, I'm going to start speedcubing again.