Advice with first property purchase please

My Fiance and I are about to venture into our first property deal and we have a few questions. We have found many properties that we could very easly make a nice profit from if we use the strategy of buy on a longer settlement re-vamp eg: carpets, paint then on sell at settlement. We have some questions about stamp duty like do we pay double in NSW. We were hoping also to talk to others that have done this type of proerty deal before. All advice is appreciated.
All the best