Getting summer-ready thighs happens faster with resistance training. This means using machines such as the incline leg press, where you rest your back on the inclined seat and push upward on the weighted press plate. If you're not feeling the burn like you think you should, check the incline to make sure you're targeting the right muscles.
Incline benches typically have markings in degrees, so check the back of the leg press bench. It should be set at 45 degrees. The top of the bench back rest should be higher than parallel to the floor, halfway between parallel and straight up.
You can leave your compass at home, even if the incline bench isn't marked with degrees to help you set it correctly. Instead, climb on and rest your back against the backrest. It doesn't matter how much weight is on the plate at this point; push up on the press plate, even if it's empty of weights, to get your legs in the proper extended position. Your knees stay slightly soft at the top of the move. Your body should make a 90-degree angle at the hips with your legs extended. Check the mirror or ask a friend to see if your body makes a corner between your tummy and thighs.
Using a leg press is sort of like learning to waltz -- you must watch your proper foot position. Your feet should fall slightly below the midline of the press plate for your body to make the correct 90-degree angle when the seat is inclined at 45 degrees. If your feet are too high on the plate, your form will be too condensed and might use more hip muscle than quadricep. If you're too low on the plate, you'll get more shin and calf action in the movement.
If your seat is set at the proper 45-degree angle, you'll have no problem bending your knees to 90 degrees as you use the leg press. Check your knee angle in the mirror or have a friend watch your movements to see if your shins and thighs meet at a perfect corner at your knee. If your incline is set too high, your knees might come all the way to your chest before they hit 90 degrees. If you're too high, you might have to fully extend your knees to reach the top of the press instead of keeping them a bit soft.