Do not use door chains. They are very weak. You can purchase strong devices which will allow you to open your door a couple of inches, but will prevent someone from pushing the door open from the outside. Consider safety film or bars on your windows. Leave outside lights on, or install motion detector lights, and keep shrubs around your doors and windows well trimmed to allow visibility to your entrances.
Criminals love the cover of darkness.
Have a safe room in your home where you can go and lock the door. Make sure you have access to a phone in this room. Having a cordless or cellular phone for this purpose would be a good idea. Never confront an intruder. Having a weapon available is NOT recommended, as it can be easily taken from you and used against you.