Tips to get Better Focus?

I have a D7000 and I normally shoot with 50mm prime lens with a wide open apeature. I like having the shallowest depth of field.

Unfortunately for me, getting everything in focus is tough. (mainly in low-light situations) I use auto focus and take something around 3-5 snaps per subject (hoping that one of those shots stays in focus). On some days, this works fine, on others not so much.

Any tips I could use?