Let's get real for a second here ladies. As women, we are constantly sizing up the competition--at the grocery store, in the classroom, and even with models on TV. Nothing stokes our egos like knowing you are objectively better than most of those women.
Don't get me wrong. This rabid competitiveness is one of the least attractive features of being a women. No one likes the moralizing (or vain) women who can never stop talking about how superior she is to some group or another. However, that does not mean that you cannot tap into this natural urge. If you're like me, empty phrases taken from shampoo ads do not inspire me to change. "Because You're Worth It" doesn't motivate me. But beating the competition does.
Use this desire NOT TO TALK about being better, but to BECOME better. Anytime you think of slipping up on your diet or exercise plan, leaving the house a mess, or getting fast food instead of cooking, remember this. Think of all the women you will be beating each time you excel.
The trick is NEVER TO SPEAK OF THIS. A key feature of poise is to not sing your own praises, and definitely to not talk smack about those who don't do these things. Maybe with your like-minded BFF, but to no one else. Remember the old adage "If you have nothing nice to say, say nothing at all."
If you practice this, you will know your value (thereby making you confident and able to graciously accept compliments), but you will also make a daily practice of being humble. It takes self control to not talk about how good you are, but it makes you much more likable long-term. Let other people notice your success, and only go into detail if asked.