Despite making some criticisms of the game, I suggest making all your survivors soldiers. The zombies that surround you keep scaling. The soldiers are the best way to keep your city from being overrun.
Starting off, I usually check to see if there's a lab, school, and hospital.
Hospital is a must. The laboratory is a second must. School is a luxury. Send the survivors with no skills with soldiers to convert them into soldiers. Convert your suburbs into farms. You'll need it once you make a radio to attract people to your base. Food and happiness are your worst enemy. They go hand in hand. If you have enough places for gathering food you can throw parties at bars to keep your morale up to prevent people from leaving.
This game on difficulty doesn't scale well and there's really no reward for doing a higher difficulty. Don't waste your time. Just do normal if you want to complete the game.
 "Rebuild"){kind=icon}