While you can manage your risk by choosing projects with a very low likelihood of surprises, you cannot guarantee that you will avoid construction surprises entirely. Beautiful Victorian homes are like horror movies for flippers, something bloodthirsty is waiting behind every wall, ceiling, and floor. Instead of trying to flip a Victorian home, look for something boring, like a tento fifteen-year old one-story ranch house with brick siding. As you gain experience, you can become more adventurous. No doubt about it, the larger profits are in the projects that scare off other people. As a beginner, though, you should be one of the scared flippers instead of one of the fearless ones.
I strongly recommend you hire a reputable, independent home inspector before finalizing your purchase. Real estate agents and mortgage brokers like home inspectors who do not make waves and flunk properties. Take recommendations from those groups with a grain of salt. Repair people like tough home inspectors who find lots of repair work. Rely more heavily on recommendations from heating and air conditioning people, plumbers, and electricians.
The most likely source of expensive surprises is rotten wood in the attic, flooring, eaves, or around windows. After that, electrical wiring in very old homes is usually substandard and must be completely replaced, not just repaired. Those same homes might have only 60amp or 100-amp service from the power company. For modern electricity loads, especially if you have electric heat or air conditioning, you will need 200-amp service. That will cost more money. Because most plumbing components are in the walls and between floors, they can lead to nasty surprises. Finally, new flippers should never try to repair old plaster. Rip it out, and replace it with drywall. Leave restoration, meaning a return to the original condition, to the experts.