In securing all outside doors, be particularly meticulous with those that offer an intruder cover — such as doors inside vestibules or enclosed porches. Here a criminal could work at leisure, safe from observation by neighbors or passersby. Be aware that these protected areas often are of less sturdy construction than other parts of your home. Ideally they should be finished off with exterior walls as sound as the rest of the house.

Every exterior door should fit its frame snugly. Most don't. House-builders sometimes take shortcuts by making the openings oversized, and even a well-fitted door can develop problems as a house settles on its foundation. The best way to remedy a poor fit is to reinforce the door frame or to replace the door with one that fits. If you don't want to go to that much expense, at least use locks with bolts that slide a minimum of one inch into the frame, or attach a common thumb lock with a long bolt to the inside face of the door. Or better yet, ask a locksmith about an L-shaped metal strip that can be attached to a door frame to protect an inward-swinging door from being jimmied with a crowbar. A flat plate attached to an outward-swinging door can be used to cover such an opening, but it should be attached with flat bolts or non-retractable screws so that it cannot be removed from the outside.

I too suggest having a home alarm. Because they provide stickers etc which itself is an alert. When you get home alarms at affordable rate it will be a wise choice. They even have features which helps even if  phone line is tampered apart from the added advantage of having Live 2-way voice communication.

it's always best to talk to a locksmith about these kinds of things they will keep your home secure and safe from burglars