You're gonna want to make the head seperate from the body. The head won't really be able to be round and 3d as it should be if it's attatched to the body as one piece. So, you should also make the nose bridge just a piece for the head and not connect it to the back.
Once you do that, you can have the body seperate and such. Make the neck like an inch or two longer than it needs to be so you can stick the head on it and it'll have support.
I'm not really sure what other tips you'd like, but I don't see a stomach piece on the pattern, which you will definitely need to add if you want the body to be 3d.