Pull-Offs

Well, other than to tell you to keep practicing, I would say to give the string a slight downward tug (toward the 1st string). My younger brother has an unusual habit, but he pushes upward. That's just the way he does it, but it works for him.

I am not sure what trouble you are having, unless it is a stretch for you. Possibly you are gripping the neck like a baseball bat. That will greatly reduce your reach, especially down at the lower frets near the nut. Make sure your thumb is on the middle of the neck, and that there is a space between the neck and your palm. It also helps to get the headstock up between your shoulder and ear. Curl your fingers over the fretboard like a spider. Perhaps this will help.

You know, there are the traditional ways you are taught to play guitar, and you should try to follow these methods if possible. But they do not work for everyone. Sometimes you have to invent your own way. For instance, you could use your pinky for that pull instead of the ring finger. Try the traditional way first though.

Don't give up. In a short while it will become very easy and natural for you, and you'll wonder why it ever gave you problems.

To expand a bit.
I don't have alot of trouble with pulls but I am with a certain one.
I am practicing a song ( Classical Gas ) and there is a pull from the 5th fret on the high E string to the open string.
I usually pull slightly accross the string like Wes suggested but it doesn't seem to work here as it tends to pull the string right off the edge of the fret board. I tried pushing up but can't seem to get that to work either.
Any suggestions?
PS: just lifting my finger the open string doesn't seem to sound well.