Like the quest for the Holy Grail, most of us are always on a mission to improve our abs.

For a while, people coveted the washboard abs gracing runways, the pages of fashion magazines, and billboards in Times Square. Now everyone is after Beyonce's flat, tight stomach.

So what does it take to get there?

Here are top six tips.

Flat Ab Tip No. 1: Improve Your Posture

Poor posture is a huge issue for many people.

For better posture while standing, align your ears over your shoulders, shoulders over hips, hips over knees, and knees over ankles. Keep the fronts of the shoulders open like a shirt on a hanger, instead of a shirt on a peg. Draw your navel to your spine and keep your weight even on the balls and heels.

The result: Without doing any abdominal exercise, you can look much leaner by simply standing up straight.

With your shoulders back and chest up, the abs pull themselves in. Your energy level improves when you have good posture. Your lung capacity is better. You're open and more awake."

Cat Kick: Stand with feet together, arms extended out like airplane wings. Exhale, and lift the right leg forward and up. At the same time, sweep the arms forward at shoulder level and round the spine, like a cat. The navel should feel as though it's pressing toward the spine. Inhale, and open back up and return to the starting position. Repeat with the left leg, alternating for 20 repetitions.

Pilates Zip Up: Stand upright with the heels together, toes slightly turned out. Bring the arms up, into an "upright row" position, hands just underneath the chin. Exhale, press the arms down (as if pressing down on a box of dynamite), keeping the hands and arms very close to the body. Simultaneously, lift your heels off the ground onto your tiptoes. Hold for two seconds at the "top" and inhale and return to the starting position. The abs go "in and up" and the arms go down. Perform 20 repetitions.

Flat Ab Tip No. 2: Think Whole-Body Exercise

When it comes to abdominal strength, you shouldn't train the body in isolation.

People have this misconception that the best way to strengthen the abs is to get on the floor and do a thousand crunches.

If we could spot reduce, our jaws would be hollow. We probably work the jaw muscle in talking and eating more than any other, and none of us have hollow jaws.

You have to see the abs as a 360-degree core. You want to develop strength and flexibility around that core.

Fitness needs to be intelligent. Do slow, high-quality exercise.

The focus is the core, but it doesn't just work the abs in isolation. That means you're using your abdominals, but you're also using your arms and legs, back muscles, and glutes.

Crunches are fine, at first, but relatively quickly, you'll have to progress to something else to get that area worked.

focus on developing not just the rectus abdominis (top abdominal muscle layer) as a crunch does, but the internal and external obliques (the side abdominals) and the transversus abdominis (the deepest abdominal muscle).

Work your core in 3-D, hitting the sides, back, and middle.

Plank: Start on your hands and knees and come up into a push-up plank position, balancing on hands (or elbows) and toes (or knees). Align wrists under shoulders; keep your back straight and the abs and glutes tight (to keep the back from sagging). Hold the position and breathe out for 10 seconds, exhaling to tighten the abs and draw the navel to the spine.

Leg Lowers: Lying supine, curl the upper body, chest over ribs, with your hands behind your head. Lift the legs up with knees bent at 90 degrees, knees over hips, ankles level with knees. Keeping the hips down, slowly lower the legs toward the floor without changing the bend in the knees, then lift them back up.

Seated Rotations: Sitting up, bend knees and legs together and place arms across the chest or in front of you. Tuck the tailbone and roll back slightly as you alternate rotating the spine right and left.

Flat Ab Tip No. 3: Examine Your Diet and Digestion

If you have abdominal fat you can have great ab strength and great posture, but you won't have a flat abdominal or a six-pack. You have to change your diet and increase your energy output.

In other words, eat less and move more.

You need to burn off more calories than you take in to reduce body fat.

Unfortunately for many people, the abdominals are a place where fat tends to accumulate.

No matter how many ab exercises you do, you're still going to have an extra layer [of fat] covering the abdominals [if you're carrying excess weight].

Flat Ab Tip No. 4: Props Are Optional

Stability balls and Bosu balls, straps and bands, even those fancy MBT Masai walking shoes are not necessary to achieve flat abs.

Props are wonderful, and they may help you work your core more readily, elevate you to a different level or simply mix it up, but you don't need them to meet your fitness goals.

Gimmicks or fancy gym memberships aren't necessary. You don't need space, you don't need sneakers, you don't need fancy clothes.

For instance, strengthen your abdominals when you're at the park, raking leaves, taking a walk. Even while socializing at a cocktail party you can stand straight and exhale to draw the navel to the spine.

Flat Ab Tip No. 5: Take Things Slow

There are no fast fixes. Even the promised quick fixes end up being temporary. It's a goal. You have to plan on a slow and steady progression.

Most people will experience set backs, roadblocks, and utter frustration along the way. Rewards come with time and consistency.

Flat Ab Tip No. 6: Set Realistic Goals

Though it's not an excuse to explain away a soft midsection, your genes do play a role. For better or worse, you stand a chance of inheriting Mom's thick wavy hair and her dark circles. Same goes for other parts of the body.

Sometimes, even very thin people can't get washboard abs. Genetically their bodies want to hold on to the extra layer on the top.

That doesn't mean you can't improve your appearance, but it does mean you need to set realistic expectations. Not everyone can look like Beyonce, but you won't stand a chance if you're still sitting around with one hand in the candy jar.

More Exercises for Flat Abs

Here are a few.

Canoe Twist: Stand upright, feet apart. Interlace all 10 fingers to the webbing of your hands to create a solid grip. Exhale, and sweep the interlocked hands, arms, shoulders, and chest to the left, as if "rowing a canoe." Simultaneously lift the left knee up and to the right. Inhale and return to the starting position. Exhale and perform the movement to the right. Alternate for 20 repetitions.