Think small. Do not think big. Build it step by step.
Start locally. Get experience. After you feel comfortable, buy one more.
It is ok to buy long distance, if you know the market. Find a property management company to manage for you.
In my city, many people from overseas(for example, Hong Kong) own properties. They have a property manager here, that is it.
My long distance property is 800 miles from me. I have a proerty manager there. I pay him 10% of the rent. All works well.
What is the secret for investing? KEEP GOING AT IT, DO NOT GIVE UP. 屡败屡战。