I found a great workout for getting your abs in better shape, which is great with Summer right around the corner.
Every workout needs a proper warm up. Warm up for about 5 minutes doing any type of exercise that will get your heart rate up (running, biking, cardio workout, dancing, etc.). Do the same for a cool down.
Start with doing moves 1-4 to get your muscles primed for the more intense ab moves. Do moves 1-4 for three weeks, and then move onto including moves 5-8, which are slightly tougher.
To get the best results, rest between each move for 30s-1 minute. Do one set of each move, and then repeat the cycle, doing every move twice. This will boost your metabolism as well as optimize fat burn which will let your abs show more prominently.
Move 1: Plank
Start in a pushup position, and lower yourself down so you are holding your weight with your forearms. Your body should be straight. Try to hold your abs in and hold the plank for about 60 seconds. If 60 seconds is too hard, try doing a plank for 30 seconds, rest for 10 seconds, and repeat.
Lie on your left side and have your legs straight. Prop yourself up with your left forearm and have your body form a diagonal line. Put your right hand on your hip and hold for 60 seconds. Repeat on the right side.
Move 3: Glute Bridge March
Lie on your back with your knees bent and feet flat on the floor. Rest your arms on the floor, palms up, at shoulder level. Raise your hips so your body forms a straight upward line (A). Brace your abs and lift your right knee towards your chest slowly (B). Hold that position for 2 counts and then lower. Repeat with the left leg. That's 1 rep. Do about 2 or 3 sets of 5 to 10 reps.
Move 4: Lunge with Rotation
Take a 5 pound dumbbell with both hands and stand with your feet hip-width apart and have your arms straight out (A). Take a big step forward with your left foot and twist your torso to the left as you bend your knees and lower your body to form a lunge (B). Twist back to the center and push off your left foot, and return to standing up. Do it with the right leg. That's 1 rep. Do 2 or 3 sets of 10 to 15 reps.
Move 5: Plank with Arm Lift
Get into the plank position and form a straight line with your body (A). Carefully shift your weight to your right forearm. Extend your left arm in front of you (B) and hold for up to 10 seconds. Lower the arm back to the original position and repeat with the opposite arm. That's 1 rep. Do 2 or 3 sets of 5 to 10 reps and rest about 1 minute in between each set.
Move 6: Side Plank with Rotation
In a right side plank position (A), reach your left hand up (B). Slowly tuck the left arm under your body and twist forward until your torso is close to being parallel with the floor (C). Return to the original side plank position. That's 1 rep. Do 2 or 3 sets of 5 to 10 reps on each side, resting about 1 minute in between each set.
Move 7: Hip Thigh Raise
Lie on your back with your right knee bent and your left leg extended upwards. Put your arms on the floor, palms up, at shoulder level with your hips about 2-3 inches off the floor (A). Raise your hips and form a straight line from your shoulders to your left foot (B). Hold for 2-3 counts and return to the starting position. That's 1 rep. Do 10 to 15 times on each side. To increase the intensity, cross your arms over your chest, instead.
Move 8: Reverse Lunge with Single-Arm Press
Grab a 5 pound dumbbell in your right hand and hold it next to your right shoulder, with your palm facing in (A). Step backward with your right foot and lower your body until your knees are bent to 90 degrees (your right knee should almost touch the floor) while pressing the dumbbell over your shoulder without bending at the waist (B). Lower the weight down to the starting position as you push back to standing up. Do 10 to 15 on the right side, and then switch to the left.
All of these moves were from Women's Health:
http://www.womenshealthmag.com/fitness/flatten-your-belly