I have one and I love it, but it took me a while to get comfortable with it. How old is your baby? It was fairly difficult for me to use when mine were really little, they seemed more comfortable after about 6 weeks. Do you have the instructional DVD? I found that very helpful. It was also helpful to have somebody help me with it the first few times.
Basically you have to treat the wrap as though the portion in the front has three parts, the back rail, which is the seam against your body, the pouch in the middle, and the front rail, which is the seam facing out. By adjusting the back rail so it's tight to you, then pulling the pouch up so it's nice and shallow, and then pulling the front rail to keep the baby in, you can comfortably hold a smaller infant.
But since its really hard to explain all that with no pictures, I really recommend you try to get a hold of the DVD. It's only about $6.00, and as weird as the instruction lady is, it really helps.