Call a licensed locksmith. They deal in home security products, hardware and such. While they don't install doors and windows, they work with them on a daily basis, and can easily spot the good doors from the junk ones.
Stay away from double doors, they are inherently weak in construction, and due to the law of physics enable burglars to get through them faster then single doors.
Quality locks especially deadbolts should be the # 1 place to start with home security, only because they are what keeps the door LOCKED. I'd rather have a medeocre door with high quality deadbolts, then the best door in the world with the "Home Depot special" locks.
Along with quality locks, the strikes need to be properly anchored to the frame. I lost count how many times I've seen good locks on decent doors, combined with strikes installed with 1/2 inch screws.
Stay away from all glass patio doors or windows low enough that someone could just "walk right in" if the glass is broken.
If you do have sliding patio doors, use a Charlie Bar. Or as a low cost alternative put a section of closet rod in the bottom track of the door.
For problematic areas where the openness of glass is desired, as well as security, clear Lexan sheeting can be affixed to the door(s) and or window(s). There are products such as window films that can be applied directly to glass to prevent it from shattering if it is broken.
(on a side note: Modern, double paned tempered glass is not very easy to break in the first place)
Clear away clutter from the perimeter of the house (large bushes, garbage cans, etc) and remove obvious "tools" that can help Mr. Burglar to get in (ladders, garden tools, bricks, etc).
I'm sorry to disagree with having the Police do a security survey, only because they generally handle "PERSONAL" security (people), and locksmiths handle "PHYSICAL" security (Inatimate objects). However, if they offer the service in your town, by all means, go for it!
As far as alarms go, they only alert you that someone is already IN your house, AFTER THE FACT!
But a decent alarm system can be worth a lot, if installed, maintained, and most importantly: USED properly.
GOOD LUCK and stay safe! --IC