I'm a guy with big hands and it was difficult for me at first too. I had to shop around for a guitar that was a little wider at the nut so I could fit my fingers on the fretboard without touching other strings all the time. Try looking at some guitars that are not so wide at the nut. Also, some guitars have necks that are fat, some are slim, narrow, wide. They are all different. Other than that, my best advice is to practice, practice, practice. Don't give up, it get's frustrating at times but you WILL get better if you practice. ;)