Am I doing the workout right?

So I am trying to lose 10lb by the end of December. I do the treadmill for 30 min straight,weights and I try to keep my time to a limit when I'm at the gym. I don't want to over do it. I get lots of compliments on my legs and everything I'm trying to get rid of some how they call it baby fat off. Any ideas like workout classes to take?
Am I doing the workout right?
Post Opinion