Are there security screens on the windows and doors? Aluminum or steel doors are preferred. Are the security doors always locked? Can all doors be opened with the same key? This can be handy for the owner, but keys should always be counted and accounted for.
Double sided locking handles are recommended for patio and sliding doors. These ensure criminal access is made even harder. What quality are the window locks? Always install the best that you can afford, and never pick the cheapest, you may come to regret it in the future. Do you have window security screens that can be left open during summer? Do you have a secure bolt system on your internal manhole/s?