My first tip is to plan out your outfits. Don't leave it until the night before you go away to decide what your taking. Roughly a week before I go away I will come up with ideas for outfits and make sure everything is washed. A good idea is to pack things that will work with different outfits, to go along with this pieces that can be layered or worn in different ways are great if you're going somewhere when you're not sure what the weather is going to be like.
I always find it helpful to lay out clothes in the outfits I plan to wear them, this again is a great way to make sure you don't pack things you are not going to wear. I also recommend checking the weather of the place you're going to. For example if it's due to be really sunny you won't need as many layering pieces like thick jumpers.
I really do love samples. Whenever I get a decent sized one I put them in a basket ready to take on my next trip. I do this especially if I get a sample of a product I love but it also give you the chance to try new things whilst you're away. REN and Origins are really good at giving out samples, especially when you order online. The Body Shop and Soap & Glory also do minis of their full size products perfect for travel.
If you don't have any samples you can always depot your products into travel containers. I tend to always do this with shampoo to save lugging around a huge bottle. Lots of places sell these containers, Boots and Superdrug have a good selection. Muji have an amazing selection and have a container for every possible need. Another good place is Primark, they do a set of different sized bottles for only a £1. I always pick one of these up as it is such a good price.
I picked up this tower of small containers from Muji recently and it is perfect for depoting creams and and foundations into to save taking lots of bottles. I think this is great if like me, you where different bases depending on your skin or the weather. It also means you can take more options without losing valuable case space. This would be great if you were just taking hand luggage and you are limit on how much liquids you can take.
So those are some tips that I use when traveling in order to save space and reduce the weight of my suitcase. Feel free to share any tips you have in the comments below.