Be cruel to be kind. Get rid of all those things that you put in the pile in with the slightest hope that maybe the pile wouldn’t be too big and you could slip them in. You’ve got to be really severe with yourself as you should be leaving with a bag no more than three quarters full.
I’m not joking, I’m deadly serious. Aim for this. If your bag is full, but not bursting at the seams, you’ll only regret it as you’ll have no room to collect all those bits of memorabilia that will appear here and there and you’ll be annoyed with yourself.
To save space and stop creasing, roll your clothes instead of folding them. You could also then place them in vacuum compression bag. To use these bags, put your clothes in, seal the bag, then squeeze the air out. This will leave you with lots more space in your suitcase and will prevent creases more effectively than folding. Stiffer fabrics, such as smart cotton shirts should be carefully folded.
You need to make use of every little inch of space that you can. Roll spare underwear, socks, other small items and make sure every possible space is filled. Don’t forget to stuff your shoes, you can squeeze quite a few things in there like socks, cables or an adaptor plug.
This is how I usually organise all of my liquids and all the fiddly bits that can take ages to dig out at security. If you want to organise your packing then get yourself a couple of ziplock bags. I have two, one for all my liquids and the other I put all my charger usb cables in.