How you field a ground ball will often be dictated by the situation and where you are in relation to the ball.
With nobody on base, and the ball hit near you, your goal is to make sure you keep the ball in front of you and field it cleanly to keep the baserunner from advancing to second. You will in this situation want to field the ball like an infielder.
With a runner at second and the ball hit sharply to you, you may determine you have a chance to throw the runner out at home. In this case you will want to field the ball off your glove hand side.
The speed at which you charge the ground ball will also be determined by the situation. If you have time to field it like an infielder you will want to approach the ball under control and get yourself in position to catch it. Even if the situation dictates that you rush to get the ball you will need to break down and get under control before you get to the ball. This will allow you to set yourself up to make a good throw which will more than make up for the time you used in slowing down.
Other problems with charging the ball at full speed are difficulties in timing your approach to catch the ball on a big hop and being able to handle a bad hop.
If you have time, make sure you try to circle the ball and keep it in front of you. With a ball hit to your side it's risky to try and take a direct angle to cut it off. If you miss judge the speed at all, the ball may get by you. By taking an angle that is deeper, you can circle behind the ball and catch it moving forward with the ball in front of you. While it might take slightly longer to get to the ball, you will be in a better position to not only catch it but make an accurate throw.
Even with the goal of trying to circle and get in front of the ball, there will be times when you will need to catch a grounder going hard to each side. Practice catching ground balls both on your forehand side and backhand side. When catching these ground balls try to keep low to the ground and your glove near the ground. Remember it's easier to raise your glove to the ball then it is to drop your glove to the ball.