Looking at a 40 liter backpack, you might think there's no way you can get even a weekend's worth of gear in there! But with a bit of effort, you'll be surprised just how much you can take with you. It's like a backpack version of a clown car. LOL
Packing efficiently, you'll have everything you need in one small bag
Clothing
Lightweight Fabrics
Clothing is a big one. You want to pack only small, lightweight clothing pieces. If you have a stack of regular clothing, and a stack of performance (or otherwise lightweight) clothing, the difference in the space it consumes and also the physical weight, is huge.A basic (and maybe not perfect) example is comparing a pair of jeans to a pair of leggings. Jeans will take up about 4 times the weight and space as a pair of leggings. Now multiply that times the number of clothing items you bring. If your entire wardrobe consists of smaller, lighter clothing, you have already saved a ton of space and weight in your backpack.
If you ever shop for performance clothing, it's not unheard of for the actual physical weight of the item to be listed. If you have a kitchen scale, you can even weigh your clothes to see the difference it will make in your bag!
Capsule Wardrobe / All Mix-n-Match
Also remember that you'll be packing a very efficient capsule wardrobe (see The Process for Creating Your Perfect Capsule Wardrobe). You don't need many clothing items. Maybe around 10 items total. That's way less than I pack for a even a weekend near home! Plan on doing laundry along the way so you also only need 1 pair of socks and 3-5 undies.Shoes
Shoes take up an enormous amount of space. You should not need more than 2 pair of shoes. Whether it's a sandal or hiker, bring a good pair of walking/hiking shoes. Then bring a pair of easy sandals (I usually bring rubber flip flops). When you are moving from place to place, if you wear your walking shoe, you only need room in your bag for your sandals.
Every ounce counts; it all adds up fast!
Toiletries & Other Stuff
It's not only about your wardrobe. All the other things you bring traveling have the potential to take up too much space and really weigh you down.Not only do you want to limit the shear number of items you stuff in your pack, but you only want to bring as much as you need (see Packing Light - What Do I Really Need?). Another important trick is to get rid of all packaging.
Let's use your first aid kit as an example. Say you want Imodium, ibuprofen, tums, a sewing kit, some duct tape for holes in your mosquito net, and bandaids. If you bought all that stuff at the store and put it in a pile, it's going to be quite a lot. But take a packet each of the medications, a small roll of tums instead of a bottle, a hotel sewing kit, only a few inches of duct tape rolled up, and a few loose bandaids and they easily fit into a snack sized ziploc with room to spare!
Same goes for any liquids. Use either travel sized shampoo, body wash, toothpaste, etc. or get refillable travel containers. If you are only going on a week-long trip, you don't even need to fill them all the way. I even bring a small sized hairbrush, tiny loofa, small small small. Only bring as much as you are going to use.
Everything you think of bringing, try to consolidate, minimize, and find smaller, lighter versions.
