DUPLEX QUESTIONS for a NewB......

[Sherfeng Vue]

I currently have one rental property. It's a duplex, 2-bedroom 1 bathroom, 1 car attached garage with an unfinished basement in each unit. I first bought the property in April of 2016 for $156,000 with an FHA loan at 3.4% with $6000 down payment. The current monthly mortgage is $1000.51 with everything escrowed. I currently occupied one side and rent the other side for $725.00, leaving me with $275.51 out of my pocket. My question is, is there any way/strategy I could lower my monthly mortgage to get a positive cash flow while still occupying one side? Maybe refinancing, paying a big lump sum such as $15,000 towards my mortgage? I have also been thinking about buying another duplex with a conventional loan and should I just save the $15,000 and continue to save to buy a 2nd duplex and rent both side of my first property to have a $449.49 positive cash flow. Also, if I do rent out the unit I am currently occupying, should I look into refinancing my duplex to possibly lowering my monthly mortgage to get a higher monthly positive cashflow? Any suggestions and tips of buying my second property other than a conventional loan would be great. Any overall suggestions, tips and input would be great. Thanks.