This is a brief article to help get you on the trail. It specifically deals with how to carry a sleeping bag as efficiently as possible in a backpack.
Steps
Method 1
When you already own both a pack and a sleeping bag
1
Make the bag small. The first consideration in packing a sleeping bag is to squish it down into as small a volume as possible. If you still have the manufacturer's instructions that came with the sleeping bag, review these and see if they give a specific way of rolling the bag to minimise the volume. If not, experiment with a couple of different ways.
2
Obtain a stuff sack. Once you think you have found a way to roll the bag into the smallest possible volume, tie it up with some light rope and take it to a local sporting goods store, where you will purchase a stuff sack for it. Buy a stuff sack that is at least a couple of inches larger around and a few inches longer than the rolled-up sleeping bag. This is important, because it's likely that you will not be able to get the sleeping bag compressed quite as small out in the field as you did in your living room at home while practicing.
3
Take your rolled up sleeping bag in its new stuff sack and all the other gear that you plan to take on a trip. The next step is to experiment with different ways to carry everything. Since every backpack is different, there's no way to describe in detail exact ways to pack one in an article like this. You will have to work it out by trial and error with your own gear. Some basics can be given:
Separate out items that won't be damaged if they get wet, like your tent and groundsheet; these can be lashed to the outside of the pack if it turns out that you can't get everything inside. The sleeping bag is likely to be the largest, bulkiest item, and since it won't be needed until you arrive at your destination, it will go on the bottom-inside of the pack.
Next pack all other items that won't be needed along the trail around and immediately on top of the sleeping bag. Hard items like cooking gear and camp stove should not be placed so that sharp corners might stick through the pack into your back or shoulders.
Small items, and anything you might need along the trail, like spare shoelaces, water bottle, snack, camera, GPS, binoculars, map, toilet paper, etc. should go in the pack's outside pockets so you can get at them without having to completely undo the pack.
Method 2
When you don't already own a sleeping bag.
1
Decide on what kind of bag you need. There are three main types: Lightweight "summer" bags that are good down to about 60ºF, three-season bags good down to about 35°F, and winter/extreme cold bags that you use when temperatures are expected to get below zero. These bags come in goose down or polyester fiber fill, and the compressibility is very different: down bags usually squeeze into a smaller stuff sack than fiber-fill bags.
2
Purchase the stuff sack. Once you have picked out a bag that fits you and is rated for the anticipated temperatures for your trip, you need to buy a stuff sack for it if it didn't come with one. Now go back to Step 2 of Method 1 and practice how to most efficiently arrange your pack and the gear you will be carrying.
