First investment Multi family home

[Garlin Thompson]

Looking to get started into Investing in real estate. First home I am looking into is a Multifamily home. My plan is to live in the home for awhile with my daughter and wife but eventually buy another and rent out the whole unit. What are main things I should look for in a home to make sure I am getting a good deal ? Also I saw where someone says whatever rent you collect you should take 50% out for cost not including mortgage. When I do math this way it seems almost impossible to find a good deal that will have cash flow although I live in southern California were prices are ridiculous right now. Any other things I should take into consideration would be helpful thanks!!