my husband and i tried to conceive for over 2.5 years before i got my wonderful positive pregnancy test this july - we're currently 22 weeks along with twins! But i remember the emotional rollercoaster that got us to this point all too well!
i'm not sure if this is the same thing as the Creighton Model, but for the first year or so we tried a method of natural family planning -- which included monitoring my basal body temperature every morning and a few other fertility signs to determine my most fertile days. Even though by itself it didn't lead to pregnancy for me, it worked VERY well... i really felt like i knew my body so much more!
Unfortunately our problems ran a bit deeper and needed more intervention. We went through everything from fertility medications to inseminations and ultimately IVF. If i could have conceived without all the stress and emotions and finances that laid on us i definitely would have, but there was a lot against us, and we decided it was the only path for us.
But for the average healthy couple, just getting in tune with your body and learning your cycles seems to be key. Learning what your most fertile days is ultimately the way to get pregnant, no matter what method you use!
www.fertilityfriend.com was a GREAT reference! It has an email "course" that can teach you everything - the what to look for and even the why it happens. And if you want to use it to its fullest you can even chart your months right online.
On top of monitoring my fertility signs, i also tried using ovulation sticks - and they really matched what my body's signs were saying.
And in the end we were having ultrasounds to watch for ovulation and those also matched right up with the temping and ovulation sticks - so its a VERY accurate method!
GOOD LUCK! and if you have any questions that my experiences might be able to help with don't hesitate to message me :)