There are a lot of great guitarists with large/fat fingers. Try to use the part of your fingertip close to the nail for fretting, by clawing your fret hand. Is it possible that you put your fingers a bit flat on the string instead of perpendicular? What kind of guitar are you using? A guitar with wider nech (and bigger string spacing) like Ibanez or Jackson may be a better fit for you, but it is mostly getting used to your instrument.[br]If you can put a picture of you fretting F or G chord, probably more people will give a suggestion.