On your form, I would suggest leaning back just a bit to get your shoulders behind the bar.
On your equipment, lose the gloves because you can't get a good grip with gloves. This will become a weak area once you get stronger and you run the risk of missing a lift. The belt needs to go next. If you are serious about lifting then you need to get a real belt. The tapered front of the belt doesn't give you anything to push your stomach against and the padded back really doesn't offer any support. You are probably just as good to go beltless. The last thing I would suggest is to take off your shoes for max attempts. You will notice almost an inch difference in the actual ROM of the lift.