Rats can be very destructive to a home and your health. They chew through walls and wires, spread disease, and are generally a nuisance. If they're sneaking around your house or other area, you need to get rid of them.
Identify problem areas around your home. Look for rat holes along the baseboards, especially in dark corners or in cabinets and by sources of water. Rats can chew and squeeze through very small openings, so don't discount a hole or crack thinking it's too small. Plug holes with steel wool; it will cut a rat's gums to chew through. Give a squirt of spray foam around that to seal.
Look for areas with rat droppings. You need to figure out where the rat party is hanging out to effectively get rid of rats. Rats will congregate where food is present and available. Place unrefrigerated food in plastic storage containers to help discourage chewing through boxes. Pick up clutter around your home; the more open your floors are, the less rats will like to be there.
Place a small dab of peanut butter on a rat trap. Wrap a small amount of dental floss or thread around the peanut butter. A lot of rats are quick enough to get the peanut butter and run before the trap snaps, but the dental floss gets caught in their teeth making it a more effective tool in getting rid of rats.
Set traps in areas near where you've seen droppings or other evidence of rats.
Use gloves when removing dead rats from your home and wash your hands thoroughly in hot water and soap (even if you used gloves). Disinfect any area in which you find a dead rat, as rats often carry diseases.