In most places, the basics of home security are, well, basic.
If you buy a new house, get the locks changed. You don't know who has keys to the old locks. If you've already been there a year or more without incident, you can probably skip this step.
Every door to the house needs a deadbolt lock. Ideally, they all open with the same key from the outside and with a thumb latch inside. This includes the door between the attached garage and the house; a garage door is not terribly secure. Be very careful with all copies of that key--don't, for instance, hand it over to your car mechanic or a valet parking attendant along with your car key--and if it's lost, you replace the locks.
Do not label keys or your key ring with anything that shows your address or allows someone to find your address online using what information is there.
Every window at ground level needs to lock.
Sliding glass doors can add security by a simple piece of broomstick laid in the track when the door is closed.
Everybody in the house, including kids, babysitters, cleaners, etc. needs to be in the habit of locking doors once they're inside. The best locks are worthless if they're not engaged. If your have household members prone to lock themselves out, consider leaving a key with a trusted friend who would be able to come over to let you in.
Do not make a burglar's chore easier by planting bushes so near the house it provides cover. Don't provide easy climbing material to upstairs windows with trellises, trees near the building, etc. Don't hide a key in a place everybody would check.
If you're going to be away, make sure someone picks up mail, flyers, newspapers, etc. that make it clear nobody's home.
Routinely keep blinds or drapes closed so burglars don't see your good stuff on a casual walk- or drive-by. Open them only when someone in the room will be using the view or daylight it provides.
If you live in a high-crime area with lots of break-ins, adding wrought iron bars over doors and windows may be a good investment.
A better investment will be insurance that replaces things stolen with new items of the same kind, not just their value as non-new items.