self dicipline is very important... you must differentiate what is practice and playing. practice is something very boring, which you play again and again and again till you master the skill. and playing with guitar is just play whatever you like for instance strumming while sing your favourite songs, well i think that won't improve your speed anyway. force yourself to keep in practice and keep the spirit all the time, with the hardwork and effort of course you can be a faster and faster player. i dun use metronomes (i usually stamping to create some beat), i just play scale and some of my favourite solo... faster and faster. i am practicing like that, do hope can help you some... :)