Fall comes every year and for us gardeners it can be a tough time of year as the plants start to fade. For me its the start of a new beginning creating a canvas in which you future garden will be painted.
Fall is the time to build up your garden for the upcoming season. 
Where to start. 
Walk Your Garden: I talk about walking your garden all season long to keep issues in check so before you clean-up make one final walk through. Document how you feel your garden preformed, what changes you would make, and what worked well. Also while its fresh in your mind write down some plans for next year. Now you are ready to get started. 
Clean-up: There are some things you want to keep and some you want to leave. Any areas where you have had an insect infestation or disease you want to remove all the plants and plant debris. Bag them and remove them or burn them. I always assume that Tomatoes and Squash have issues so I remove them. 
Root crops can stay in the ground all winter. During a mild winter you can harvest all winter or wait until Spring and harvest. 
There are 2 schools of thought on what to do  with the rest of your garden space. 
The traditional method is to pull all the annual plants, Beans, Peppers corn etc. and lightly rototill or hand turn soil ( do not work soil more then 4" down) rake it out and then cover with leaves and or manure. If you have a really weedy area you can cover it with black plastic to kill off the weeds. If you have wet heavy leaves or grass clippings you can put cardboard under the leaves. Beware windy weather. If your garden does not have a fence around it you can buy some inexpensive construction fence to keep leaves from blowing away. In the Spring you can rake the top layer of leaves off reveling a rich day soil layer under to plant in. You can put overwintered leaves between your freshly planted rows or put them in your compost pile. 

Method # 2 has us leaving the plants in place over the winter. There is a fungus amongus so to speak. Mycorrhiza(“root fungus”.) resides in a healthy garden. Whether fungus makes you think of yellow toenails or mushrooms on a pizza, most don’t realize the impact they do and can have on all life on Earth. They are an amazing life-form that we are just scratching the surface of their potential. One use that commercial growers and nurseries have known for a while but is now starting to trickle to us gardener is the symbiotic relationship mycorrhizal fungi has with plants. So the idea of leaving roots in place over winter makes sense. Another concept is to insert more perennial plants in the garden to host this healthy garden fungus. The idea is to still remove any diseased or infested plants but leave the others in place and then cover with leaves and or manure. The bonus is some roots will rot, and some will host the Mycorrhiza. The plants left standing will also hold leaves in place. In the Spring you can rake out the garden cleaning up the bigger plants and roots and getting ready to plant. 
Either way you go adding more organic material and covering up your garden to deter early weeds will make Spring planting go better. 
What to do with perennials: Many plants will over winter in the garden. Plants like Sage, Thyme, Oregano, Lemon Balm, Tarragon and Chives need no real care and they will come back in the Spring. Rosemary & Lavender fair well during a mild winter, but I like to pot mine up and put them in my greenhouse or enclosed porch. Do not water them very much because unless you are giving them heat and light its best to let them go dormant. If you try to leave them out for the winter try covering them with leaves or straw. 
Trees: As you grow your orchard or just increase your tree canopy its important to protect your tree trunks. I used to roll the dice and hope that my trees did not get chewed on by rabbits or deer over the winter, but then a few years back when we had a really hard winter the rabbits took the bark off several tree and killed them. Yep I knew better. So I now go to Menards and buy these fancy tree trunk covers made from corragated pipe. There are several ways to protect your young tree trunks. The key is that air needs to flow around tree, water can't stand around trunck, and be sure it does not restrict growth. 
Berries: 
In early to midfall, prune summer-bearing raspberries, leaving six of the strongest brown canes for every 1 foot of your row.
Prune fall-bearing raspberries ruthlessly, moving them to the ground after they have borne fruit. New canes will come up in the spring. 
If in doubt wait until Spring and cut all the dead canes out and lightly mulch around the bushes. Of course wait long enough to make sure you are cutting just dead canes. 
Plant blackberries in the fall and mound up the soil around the canes to prevent hard frosts from heaving them out of the ground.
Cover strawberry beds with straw or hay.
Garden Odds and Ends:
1. Empty all your outdoor containers to keep them from cracking during the winter. Store them upside down.
2. A bucket or hanging basket hung in the toolshed is a great place to store hose nozzles and sprinkler attachments.
3. On a mild day, run your garden hose up over a railing or over the shed to remove all the water. Then roll it up and put it away.
4.Cover your compost pile with plastic or a thick layer of straw before snow falls. this will keep it active longer into the winter
5. Scrub down and put away your tools. Some folks oil their tools with vegetable oil or Beeswax to keep them from rusting. Winter is also a great time to get tools sharpened. 
** Just an FYI there is a great guy at The South Bend Farmers Market that sharpens tools. 

One more thing ! 
If you just can't let your garden go try some season extenders Focus on cool weather crops like Kale or Spinach trying to extend warm weather crops just does not work.. Just don't forget it does not rain under the season extender so keep it watered.