Hi Tony. Post 21 Lovemymartins advice is spot on. The action on some of the cheaper guitars is set up terrible. The strings are too high above the fret board, which causes the muting of other strings when forming chords. Once set up properly you will learn a great deal quicker guaranteed (no more muting).
i have adjusted the action on two friends £80 guitars recently and they now play sweet. it is something you can do yourself, the info is on the WWW and its really simple. Or a visit to your local shop and they should sort the problem out for under £30.
As to the other advice, practice practice practice, totally correct. I am a newbie myself and totally enjoying the experience. would like to stay in touch and swap experiences if you are interested and any other newbies who are reading this.
My biggest problem to date is the strumming. I am left handed but my wife purchased a right hand guitar so i stuck with it. the only reason being if I go to a party and there is a guitar there, the chances are its a right handed guitar. it feels totally alien but im sticking with it. first song House of the rising sun.
Good luck and hope to hear from you.
