i have been playing the guitar for a year and am self taught. i wanted to make my own solos. some people said just fool around, others said fool around but with a scale. my experience told me that the second option is better. i have started to learn some basic scales like major scales and i just improvise on them and i am getting somewhere with regard to making riffs, even though they r only slow riffs which would only be suitable in intro and outros and i think they would be better with flanger.anyway, learn a scale and improvise on it and it will get u somewhere. to learn more on scales i would suggest cyberfret.com which has a lot of gr8 lessons......so take the advice and use theory
[WARNING!!!! but dont try to take in more than u can handle!!!!!]