Hi Marion. The trick (and there are a thousand tricks) is to only practice it for about a minute or two a day...but EVERYDAY. You'll learn it.....but.....you need the Barre F as well. There are things each can do that the other can not. Hang tough.

The main thing that I try to emphasise to my students is that the Thumb F is THE HARDEST THING YOU'LL EVER HAVE TO LEARN ON A GUITAR. Nothing else comes close. So when you DO master it, your sense of self-accomplishment will be immense.

One more little trick that I may or may not have mentioned in this thread. And this REALLY works.

Run your index and middle finger up and down the back of your guitar neck..to the point where you can really feel them stretching. Then do it with your middle and ring finger. tthen your ring and little finger. Once a day for about twenty seconds. Your finger span will increase noticeably within a couple of weeks. To test the results, play a four string Gmaj7. Index on the ist string second fret, middle on the second string 3rd fret, ring on the 3rd string fourth fret, pinky on the 4th string fifth fret. Should be damn hard at first. After a couple of weeks of the finger streching excercises you'll get it easily. The Thumb F shouldn't be far behind.

Rick