Leg presses will help, but with a twist.
First, try having your feet facing straight up and about hip distance apart.
Then turn your feet, knees and hips out (think like a ballet dancer), also hip distance apart, and repeat.
Then turn your feet, knees and hips inward, and repeat again. This is usually the hardest.
The reason for this is that there are 4 different muscles that make up the quads, and thre tham make up the hamstrings. Usually 1-2 of these gets worked more than the others. By changing the position of your legs you can rebalance the joints and function better.