S.M.
Molly gave the best advice and I only have to add to be patient with coaxing her to open wide.
The trick really is to pull her in, it almost feels like you are smashing her against your breast. Of course you are not, but it seems that way at first. It really does work.
If you can't figure it out call a La Leche League Leader in your area. They are free assistance for bf moms. Check out the website, www.llli.org.
good luck