My wife could never reach her g-spot manually. It wasn't until I gave her the Pure Wand that she 'found it'. Observations from my wife:
Always have an empty bladder. The g-spot is referred to by many doctors as the 'urethral sponge'. This is because the g-spot is an erectile tissue mass that surrounds the urethra. Direct pressure on the g-spot will give most women the urge to urinate. Knowing the bladder is empty allows the woman to get through this urge and enjoy the pleasure that comes when the urge subsides.
Use the large end - the small end can certainly apply pressure, but the large end provides my wife with full-coverage - and maximum pleasure.
The most success comes from using rocking motions - as opposed to thrusting motions. There are several ways to do this. One is to move it to rotate the external shaft from side to side. Another is to move in-and-out in very short strokes - an yet another is to hold it in place and have her rock her hips.
I had my wife learn how to use it on her own - then teach me. Since she is a teacher (3rd grade), I tease her with the teacher fantasy. But in this case ti had a very practical benefit for us both.
If you send me your email address I have a PDF of a collection of reviews from various sites that describe how various women use the Pure Wand - that I can send you.