To tone your thighs fast - three words ladies - squats and walking lunges. I took a fitness bootcamp for women last fall. We met three times a week and these two exercises were at the core of each meeting. My husband noticed a difference after week one. At the end of the second week, I was in pretty good shape and he was telling me how hot I looked.
Walking lunges: Keeping your back straight and hands on your hips, take a step forward with your left foot while bending your left knee until the knee is just over the ankle. Your thigh should be parallel to the floor. Keep your abs pulled in tight. Your right (back) leg should be slightly bent but not touching the ground. See the photo. Now pull your right leg forward until back in an upright position. Repeat with your right leg. Keep alternating moving forward doing as many as you can. Take it easy, going slowly to make sure to keep your posture in check. Keep a mental note of how many you were able to do the first time.
Squats: With your back straight and arms outstretched in front of you, feet hip-width apart, toes facing straight ahead or angled slightly outward, slowly bend the knees and lower hips towards the floor, keeping your torso straight and abs pulled in tight. Lower yourself until your thighs are parallel to the floor. Do as many as you can, going slowly and keeping your posture in check. Keep a mental note of how many you did.
Repeat these two exercises three times a week increasing your "record amount" each time.
Keep doing this and I promise, you will see results. These are the two best leg exercises you can do to get your lower body in shape quickly.
Add bike riding to your routine. You don't have to buy an expensive bike to get the benefits. Walmart has bikes for less than $100.00. Pedaling a bike works your thigh muscles quickly. Plan on riding your bike several days out of the week. Start out going short distances and work your way up to longer treks.