1. Use your packing list to make sure you don't leave anything behind on the way back.
2. Or utilize your bullet journal for a more thorough prep.
3. Choose outfits based on activities, not days.
Instead of packing based on days gone, I pack based on the type of activities I'll be doing. For a recent trip to Europe, I knew I'd be mostly sightseeing so I packed two typical sightseer outfits and only one going out/nice outfit. Yes, you'll be wearing the same outfit multiple times, but throw in a couple of layering items like cardigans or scarves and it can last a whole week, or even two. Waist-up accessories can hide the fact that you've been wearing the same thing in every single vacation selfie.
4. Bring less clothing and do all your shopping when you travel.
5. Stow each day's necessities in separate plastic bags.
6. Or recycle the packaging from sheet sets.
Any time I buy new sheet sets or other bedding stuff, I always save the zippered bags they're packaged in. They work perfectly for packing anything that might leak. They're also great for packing shoes!
7. Wrap your jewelry around cotton swabs to prevent tangles.
8. Bring half of what you think you need.
I make a pile of everything that I think I'll need, and then only pack half of that.
I've spent months backpacking around the world with just one backpack and it's a system that has never failed me.
9. Pack in advance so you have time to reevaluate.
10. Or put everything in a massive vacuum-sealed bag.
11. Wash each outfit in the sink and let it dry overnight.
12. Avoid packing jeans if you can.
Lose the denim! Seriously, jeans are heavy. Instead, pack leggings, soft fabric pants, and cardigans. Not only will it make your luggage lighter, but it will also save you heaps of space.
13. Use packing cubes to avoid destroying your organized bag the second you step in the hotel room.
14. And leave your ball gown behind. You aren't going to wear it.
15. Prepare for the worst with your first-aid necessities.
16. Keep necessities in your carry-on.
Always pack spare underwear and a toothbrush in your carry-on. I've been stuck overnight too many times!
17. Keep your bra's shapes by nesting your socks in the cups.
I roll my underwear really small and put in the cup of my bra like a bowl. Shove it in a back corner like a little bra hut.
18. And use a carabiner to attach bags or shoes that don't fit onto your luggage.
If I'm not flying, then I attach some of my shoes to my bag with a carabiner. All of my beauty/bathroom stuff has its own small travel bag that either goes in a backpack or is also attached by carabiner.
Here are some carabiners with screw locks for $9.98.