If you're using one that has a very small area supporting her pelvis (like most sold at baby stores), I would highly recommend switching to the Ergo. Right now she would probably be most comfy with the newborn insert, so she's not really *sitting*.
I used a hotsling (before they went all mainstream and sold at stores) but it was never fitted right so was only marginally comfy. I got into mammasmilk slings just before DS decided that slings weren't his thing anymore, LOL.
I had a mei tai and that was great; the body was several layers of mesh, so it was my
Disneyland baby carrier. Alas, the straps were UNpadded, which caused awful hickey-type marks on the front of my shoulder/armpit area...definitely go for padded shoulder straps!
I liked my MobyWrap, but not for Disney. My festival wrap was just a big length of cotton batik fabric that I tied like the Moby.
The most important thing for babywearing at the beginning? Get yourself entirely dressed, down to shoes, etc. Have baby ready. Everyone is fed, has used the bathroom or has fresh diapers, etc. Put sling on, baby in, and get OUTSIDE! Nothing drives a baby crazier than just standing around in their sling/carrier especially when everyone is still getting used to it.