spend a day in a big department store and go round to all the counters.. ask their advice. they will try to push their products on you, but at the same time they will all analyse your skin and tryproducts on you for free and recommend certain things. You will soon learn what kind of cleanser you prefer (gel, cream, foaming, bar etc) how thick you want your moisturiser and by trying them on you will know what you are happy to buy.
same with makeup.. a good foundation is the basis of everything (apart from skincare) if you are super dry get a hydrating foundation but also be aware that when your super dry, you will produce oil in the cabin (because it simply is so dry your skin trys to over compensate itself) so you might want a small powder compact for touchups.
Your skin changes when your flying.. it does strange things to it being in a drycabin for so long so dont be suprised if your skin changes quite dramatically.
once you have decided what products you like, order it from
www.strawberrynet.com or duty free.
remember, you dont have to have all skincare items from same brand.. thats a myth. but make sure you get a cleanser suited to your skintype, if it dosent remove makeup properly get an eyemakeup remover too and a good moisturiser with SPF, or use SPF in addition to your moisturise. Clinique do a great CityBlock that you can pat over your moisturiser and use alone as a tinted moisturiser when your not working.
This time of year is perfect for shopping because its Gift with purchase time everywhere! so you should get some good deals!