As has already been stated a pull is caused by a downswing path that is outside-in. You need to now guard against trying too hard to swing inside-out else you'll push (this used to happen to me a lot, going from one extreme to the other trying to fix each one)

A great drill is to take two clubs and lay them parallel to the target line against each heel. So that you have a club pointing to the target line against your left heel (for righties) and one away from the target next to the right heel . Now when you put a ball down you will see there is a natural semi circle formed between the 2 clubheads through the ball. Swing back halfway to parallel trying to get your arms over the club alongside your right heel and get the wrists fully cocked so the club is poitning to the sky. Now TURN through the ball so that the clubhead is parallel with the forward facing club and fully extended. This is inside to inside, along that semi circular path. Try and learn what it should feel like through impact. Hit balls with this halfswing and only stop when you can bit say 20 or 30 with great contact and good ballflight. If you cant get this right with halfswings there is NO point in trying a full swing. Then when you feel really comfortable with these half swings, start taking the club further back with your shoulders and pump down to that same halfway position in the downswing, all the time keeping those clubs in place and again go inside to inside through impact. Again do this a lot without a ball to 'feel' what you body does to get the club back to halfway down in the right position (clearly you should be moving forward and keeping some c*ck in the wrists). From there you go through impact again on your tried and tested half swing drill

An extension of this drill is to do this with a headcover under your left armpit to stay connected on the backswing and not get armsy. Vijay does this endlessly

ALL great players and pros are in these positions from hip high downswing to hip high forward swing. They may go over or below the plane as they get to the top (Furyk, Fuzzy etc) but all will reroute back to this point halfway down

Hope this helps