Keep external doors well lit when you are not at home. This will discourage intruders. Movement-activated floodlights are also a terrific idea. Make sure, however, that the burglar cannot access the electricity supply and thereby shut down all lighting. Ensuring your walls are free of attachments will deter burglars from climbing up to windows, etc. in order to enter your home.
High fences can give protection to burglars.
Try to ensure your house remains visible from the street - in this way neighbours can also keep a watch over your property. Position trees and large shrubs away from the house so that these do not obscure windows. Noisy gravel pathways can alert you to unwelcome visitors. Dogs are another wonderful way to be warned of intruders. If your house backs onto a rear lane, make sure that you lock your back gate at all times.