Drain hoses and store in a shed or garage. Remove watering wands, spray nozzles, and connections (quick connects, Y's, etc.). Drain, and store indoors.
Tuck underground parts of tender plants, like dahlia, gladiolus, or canna, into moist peat moss or sawdust. Store in a cool, dark place. Check roots monthly; toss any showing soft spots or rot.
Pull plant supports and stakes. If possible, store these items outdoors -- freezing temperatures should kill any overwintering pests and diseases.
Ideally, store frost-sensitive containers in a garage or shed. Empty and clean pots first. If indoor storage isn't an option, swaddle pots in bubble wrap, tuck into garbage bags, and store upside down in a protected location outdoors.
Test Garden Tip: Store used potting soil from container gardens in an uncovered trash can with some holes drilled into the base for drainage. When dumping container gardens, toss plant tops into the compost and dump soil into the can. Roots will compost over winter.