Whether you're traveling the world or going on a long weekend, packing the right things has a huge impact on your trip. Pack too much and you're carrying dead weight for the whole trip; too little and you don't have the things you need.
When I pack, I start at the very beginning: the bag. If you're flying, what are the size restrictions for your luggage? If you're driving, how much space do you have in the car for your stuff? If you're taking a train or a bus, what can you walk around with realistically? Once you figure out if you're using a suitcase or a backpack (or anything in between), you can visualize how much space you actually have for this trip.
Start with the essentials: things that tend to be forgotten when in a time crunch, but you can't live without. For example, socks, underwear, your passport for international trips, your phone charger for all trips. Packing them first ensures that you remember them and shows you how much space you have for your clothes and (maybe) extras.
Think about your clothing before putting anything in the bag. Will you be able to do laundry where you're staying? If so, you don't need a different outfit for each day. You can just wash things halfway through the trip and cut down on the amount you need to pack.
No laundry, no problem! You can still back light. Think about things that can be mixed and matched and layered. This is the time to let your basics shine! Try to avoid bringing that skirt you really only like with only one top. It might look great for one day, but it doesn't help you save space. Focus instead on things that can be worn in more than one way, like a denim shirt you can throw on if the temperature drops a bit or a sun dress that can be dressed up or down depending on the plan. If you're worried you'll look too plain, you can always pack a scarf or two to brighten things up. Scarves are easy to pack and make it hard to tell you wore the same shirt three times this week (when laundry's tight, you gotta do what you gotta do).
Shoes are also important to your trip. When playing tourist, I always vote function over fashion. You're photos may not be as cute, but you won't end the day early because your feet hurt. Another easy thing to pack is flip-flops. They can work as shower shoes, or slippers if the floor is cold, or back up shoes if you walked too much and can't get your feet back into your sneakers (it happens sometimes). Either way, the important thing is that shoes take up a lot of space so every pair you bring needs to be one you can wear for more than one day.
If you've packed your essentials, basics, and shoes and still have room, you can throw in some extras. Think an extra pair of shoes in case you end up at a nicer restaurant, an extra sweater in case its colder than you expect, more snacks for the plane. Don't pack too many things though because you'll want space for souvenirs!
Packing light takes time and practice. Take a minute when you get back from your trip to think about everything you brought and what you didn't end up needing. Then remember not to pack that for your next one. Every trip is different and weather can change unexpectedly, so don't get hung up about bringing a rain coat you never needed or an extra shirt you didn't end up wearing. The goal is to bring what you need to enjoy the trip and once you've packed, it is just to enjoy the trip, not to stress about how you should have packed.
A rough packing list:
Essentials: Basics Extras
Toothbrush Tops Flip-flops
Tooth paste Bottoms Reusable water bottle
Deodorant Sweater (weather-dependent) Camera (not on your phone)
Hairbrush Jacket (weather-dependent) A book
Underwear Hat Travel journal
Socks Sunglasses Snacks
ID Bag (other than your suitcase)
Phone charger Shoes
Soap (trip-dependent) A stripped down version of your make-up bag
Your sense of adventure!