I am very new to Geocaching too. I started a couple weeks ago and have found every one I hunted for, about 16 I guess, except one.
I have found that with my gps, garmin GPS lll, I can get pretty close but not right on top of it. I walk it in slowly and then just put it in my pocket. Then I stand in one place and ask myself, "Where would I hid it?" Then I look for something that does not look right, bark along a tree trunk or just something that draws the eye.
Sometimes my GPS has me fifteen or twenty feet away and it is not always my GPS that is off. I think it also is the GPS that the person hiding the cache that might be different and also if the person hiding the cashe lets the GPS settle down before marking it.
I don't expect the gps to find it for me but use it to get me in the area and then the fun begins.
Take time to learn your unit too. It will come to you and it is a ball. I don't know how much I will do in the summer as I have lots of summer interests but it sure is the thing in the winter on nice days.
Good luck